Your First Basic CALCULUS Problem Let’s Do It Together….

TabletClass Math
3 Dec 202120:46

Summary

TLDRIn this educational video, the host John introduces viewers to calculus, emphasizing its beauty and power despite its reputation for difficulty. He presents a basic problem involving a ball's trajectory to illustrate the concept of finding maximum altitude using calculus. John explains the importance of the derivative in calculus for determining slopes and how setting the derivative to zero helps find the vertex of a parabola, representing the maximum point. He also touches on the significance of good math notes and offers resources for further learning, concluding with an encouragement to appreciate and possibly pursue the study of calculus.

Takeaways

  • 📚 The video aims to introduce the viewer to the power of calculus, a subject often considered advanced but with understandable and beautiful concepts.
  • 🔍 The speaker, John, is a middle and high school math teacher and founder of tabletclassmath, offering comprehensive online math help programs.
  • 📈 John emphasizes the importance of good math notes for students, as they are often correlated with better math grades.
  • 🤔 The video presents a basic calculus problem involving finding the maximum altitude of a ball fired into the air, illustrating the practical application of calculus.
  • 📉 The concept of the derivative in calculus is introduced, which is used to find the slope of a curve at any given point, essential for identifying maxima or minima.
  • 📶 The derivative is calculated for a given quadratic function, demonstrating how to find the first derivative using algebraic manipulations.
  • 📈 The process of setting the derivative equal to zero to find the vertex (maximum point) of a parabola is explained, showcasing a fundamental calculus technique.
  • 📊 The video simplifies calculus concepts to make them more approachable, aiming to inspire interest in the subject and its real-world applications.
  • 🚀 John highlights the importance of calculus in modern technology, asserting that without it, many of our technological advancements would not be possible.
  • 🔗 Links to John's math help program and comprehensive math notes are provided in the video description for those interested in further learning.

Q & A

  • What is the main topic of the video?

    -The main topic of the video is calculus, specifically introducing viewers to the power and beauty of the subject, and demonstrating how calculus can be used to solve problems, such as finding the maximum altitude of a ball thrown into the air.

  • What is the reputation of calculus according to the video?

    -Calculus has a reputation of being advanced and difficult, but the concepts and principles are understandable and beautiful.

  • Who is the presenter in the video?

    -The presenter in the video is John, the founder of TabletClass Math and a middle and high school math teacher.

  • What is the purpose of the video?

    -The purpose of the video is to introduce viewers to the power of calculus and to solve a basic calculus problem together to illustrate the concepts of the subject.

  • What is the significance of math notes according to the video?

    -Math notes are significant because students with the best math notes almost always have the best math grades, and vice versa.

  • What is the primary concept used in the video to solve the problem?

    -The primary concept used in the video to solve the problem is the derivative, which is used to find the slope of a curve at any point.

  • What is the derivative in the context of calculus?

    -In the context of calculus, the derivative is a concept that allows us to find the slope of a curve at any given point, which is instrumental in identifying maxima, minima, and other critical points.

  • How does the video demonstrate the use of calculus to find the maximum point of a parabola?

    -The video demonstrates the use of calculus by finding the first derivative of the function representing the parabola and then setting the derivative equal to zero to find the x-coordinate where the slope is zero, indicating the maximum point.

  • What is the role of integration in calculus as mentioned in the video?

    -Integration in calculus is used to find areas under curves, which is a powerful tool for various applications, although it is not directly used in the problem demonstrated in the video.

  • What is the importance of calculus in modern technology according to the video?

    -Calculus is crucial for modern technology as it has solved numerous technical problems and is foundational to many innovations; without calculus, many of our modern conveniences like cellphones and airplanes would not exist.

  • How can viewers find more math help from the presenter?

    -Viewers can find more math help from the presenter by following the links provided in the video description, which lead to comprehensive math notes and video-based math help programs.

Outlines

00:00

📚 Introduction to Calculus

The speaker introduces the topic of calculus, acknowledging its reputation for being advanced and difficult, yet emphasizing that its concepts are understandable and beautiful. The video aims to demonstrate the power of calculus through a basic problem involving a ball's trajectory, aiming to find its maximum altitude. The speaker, John, introduces himself as a math teacher and founder of Tablet Class Math, offering online math help programs and comprehensive math notes. He stresses the importance of good math notes for students, sharing his experience that well-organized notes often correlate with better math grades.

05:03

📈 Understanding the Derivative in Calculus

This section delves into the concept of the derivative in calculus, which is fundamental for finding the slope of a curve at any given point. The speaker uses the analogy of a roller coaster to explain how the slope changes along the curve, reaching zero at the peak, which represents the maximum point or vertex of the parabola. The derivative is introduced as a method to mathematically determine this point of maximum, contrasting it with algebraic techniques that can also find the vertex of a parabola.

10:04

🔍 Calculating the First Derivative

The speaker demonstrates how to calculate the first derivative of a function, using a polynomial function as an example. The process involves applying calculus rules to manipulate the function and derive a new formula that represents the slope at any point on the curve. The speaker simplifies the process, making it accessible to viewers with some algebra background, and emphasizes that the first derivative will help identify where the slope is zero, which corresponds to the maximum point on the curve.

15:05

🎢 Finding the Maximum Point of a Parabola

The speaker applies the concept of the first derivative to find the maximum point of a parabola, which is akin to finding the peak of a roller coaster's path. By setting the derivative equal to zero and solving for the variable, the speaker determines the x-coordinate where the slope is zero. Substituting this value back into the original function yields the y-coordinate, pinpointing the vertex of the parabola. This example illustrates a practical use of derivatives in calculus to solve real-world problems, such as optimizing trajectories.

20:06

📖 Conclusion and Encouragement to Learn Calculus

In the concluding part, the speaker summarizes the video's lesson on using the first derivative to find the maximum point of a function. He reiterates the importance of calculus in various fields, emphasizing its foundational role in modern technology. The speaker encourages viewers to appreciate calculus and consider learning it, acknowledging the subject's complexity but also its significance. He invites viewers to engage with his YouTube channel for more math content and offers his best wishes for their mathematical endeavors.

Mindmap

Keywords

💡Calculus

Calculus is a branch of mathematics that studies how things change. In the video, calculus is introduced as a powerful and advanced subject that is fundamental to understanding many scientific and technological concepts. The video aims to demystify calculus by explaining its basic principles and showing how it can be used to solve problems, such as finding the maximum altitude of a ball thrown into the air.

💡Derivative

The derivative in calculus represents the rate at which a function is changing at any given point. It is used to find the slope of the tangent line to the graph of a function at a specific point. In the video, the derivative is used to determine the maximum point of a parabolic trajectory, illustrating how calculus can be applied to real-world physics problems.

💡Integration

Integration is the concept in calculus that deals with finding the area under a curve defined by a function. It is one of the two main operations in calculus, the other being differentiation. The video mentions integration as a powerful tool for calculating areas, which is essential in various scientific and engineering applications.

💡Algebra

Algebra is a branch of mathematics that uses symbols and rules to solve equations and manipulate expressions. In the video, the presenter mentions that some basic algebra is necessary to understand calculus concepts, particularly when dealing with the manipulation of equations to find derivatives or to solve for specific values.

💡Parabola

A parabola is a U-shaped curve that can be described by a quadratic equation. In the video, the concept of a parabola is used to illustrate how calculus can be applied to find the vertex of the curve, which represents the maximum or minimum point, depending on the context.

💡Slope

Slope in the context of calculus refers to the steepness or incline of a line, which is a fundamental concept when studying the tangent to a curve at a specific point. The video explains how the slope changes along a parabola and how the derivative can be used to find the exact slope at any point, particularly where the slope is zero, indicating the maximum or minimum.

💡Vertex

The vertex of a parabola is the point where the curve changes direction, which is the highest or lowest point on the graph. In the video, the presenter uses calculus to find the vertex of a parabola, which is a practical application of derivatives to determine the maximum altitude of a projectile.

💡Tangent Line

A tangent line is a straight line that touches a curve at a single point without crossing it. In the video, the concept of a tangent line is used to explain how the derivative provides the slope of this line at any point on the curve, which is crucial for understanding the local behavior of functions.

💡Maximum Altitude

Maximum altitude in the context of the video refers to the highest point a ball reaches when thrown into the air. The video uses this concept to demonstrate how calculus can be used to solve a physics problem by finding the vertex of a parabolic trajectory, which represents the maximum altitude.

💡Math Notes

Math notes are records of mathematical concepts, formulas, and problem-solving strategies. The video emphasizes the importance of having good math notes for students, suggesting that well-organized notes correlate with better mathematical understanding and performance. The presenter also offers comprehensive math notes for various levels of mathematics.

Highlights

Calculus is considered advanced and difficult but its concepts are understandable and beautiful.

The video aims to introduce viewers to the power of calculus.

A basic calculus problem involving a ball's trajectory will be solved.

The video includes some basic algebra, suitable for viewers unfamiliar with calculus.

Introduction of the speaker, John, founder of TabletClass Math and a middle/high school math teacher.

John offers an online video-based math help program and comprehensive math notes.

The importance of having outstanding math notes for students is emphasized.

A problem involving finding the maximum altitude of a ball is presented.

Integration and derivative are introduced as the two primary concepts of calculus.

The derivative is used to find the slope of a curve at any point.

The concept of slope in the context of a parabola is explained.

The maximum point of a parabola is analogous to the top of a roller coaster.

The process of finding the first derivative of a function is demonstrated.

The first derivative provides a formula for the slope of the function.

Setting the derivative equal to zero helps find the maximum point of the parabola.

The maximum point of the parabola is calculated to be at (-4, 7).

Calculus is essential for modern technology and has wide-ranging applications.

The video concludes with an invitation to subscribe and explore more math content.

Transcripts

play00:00

okay let's talk about calculus and if

play00:03

you're watching this video i assume

play00:05

you're interested in the subject of

play00:06

calculus maybe you're planning on taking

play00:08

a subject or maybe you're just kind of

play00:10

just generally interested on

play00:12

the math called calculus and

play00:15

calculus has kind of a reputation of

play00:17

being advanced and difficult and in fact

play00:19

it is but the concepts and principles

play00:22

are actually um

play00:24

pretty you know understandable for

play00:25

anybody and they're very beautiful it's

play00:27

a calculus such a powerful

play00:29

mathematics so the whole point of this

play00:31

video is to kind of introduce you to

play00:34

some of the power of uh calculus okay

play00:37

and we're going to be doing uh something

play00:40

here it's gonna be kind of a little

play00:41

basic interesting problem and if you've

play00:43

never done

play00:44

calculus before stick around because

play00:46

this could definitely be your first

play00:48

calculus problem and we'll kind of

play00:50

solve it together but

play00:52

i will say in full disclosure then i'm

play00:55

going to be doing some

play00:56

algebra not much okay some basic algebra

play00:59

in this problem so if you're not

play01:01

familiar with algebra still stick around

play01:03

okay you'll learn something but if you

play01:05

know some algebra you'll kind of um

play01:08

relate to some of the things going to be

play01:10

talking about here in a second but first

play01:12

i'm going to quickly introduce myself my

play01:14

name is john i'm the founder of tablet

play01:16

class math i'm also a middle and high

play01:18

school math teacher and over many years

play01:20

i've constructed what i like to believe

play01:22

is one of the most robust comprehensive

play01:24

online video based math help programs

play01:26

there is now of course i'll let you be

play01:28

the judge of that if you want to check

play01:30

it out but

play01:32

you can find a link to my math help

play01:34

program in the description of this video

play01:36

but whether you need to take a full

play01:37

comprehensive math course i can help you

play01:39

or you need assistance in the course you

play01:40

might be taking right now i can help you

play01:43

all my

play01:44

courses have full comprehensive lessons

play01:47

and i teach you how to solve the most

play01:48

common

play01:49

type of problems you're going to be

play01:50

facing

play01:52

at the middle high school level or even

play01:53

more advanced levels okay i literally

play01:55

solved thousands of problems and i think

play01:58

that's where uh my program is very

play02:00

unique okay not many programs really

play02:03

have that much video content but again

play02:05

if you're interested you can follow the

play02:06

link in the description below okay now

play02:09

let's talk about math notes if you are a

play02:11

math student you may or may not be but

play02:13

if you are a math student you need to

play02:16

have

play02:16

outstanding math notes okay after

play02:19

decades of teaching math one thing is

play02:21

apparent to me those students with the

play02:23

best math notes almost always have the

play02:25

best math grade

play02:27

grades and the reverse is true okay

play02:29

those students with no math notes uh

play02:32

sloppy disorganized math notes and that

play02:33

was mean way back in the in the day i to

play02:35

learn how to take math notes and that's

play02:38

maybe your situation okay so if your

play02:39

notes are not that great don't get down

play02:43

on yourself too much just recognize that

play02:45

you have to start improving okay but in

play02:47

the meantime you need something to study

play02:49

from so i actually offer very

play02:51

comprehensive detailed math notes you

play02:52

can find a link to those in the

play02:54

description of this video as well those

play02:56

include pre-algebra algebra 1 geometry

play02:59

algebra 2 and trigonometry okay so let's

play03:02

get into this problem and you might be

play03:04

saying well what is this problem okay

play03:06

well here

play03:07

let's just imagine we had like some ball

play03:10

getting fired up in the air maybe a

play03:12

cannon or something and this ball was

play03:14

traveling up and up and up and up and up

play03:16

okay and then it kind of peaked and now

play03:18

it's on a way back down right so

play03:21

uh let's

play03:22

try to identify at what point

play03:25

does this ball reach its maximum

play03:28

altitude okay that's kind of the general

play03:30

idea here uh again it's not going to be

play03:32

an exact this would be like an example

play03:35

of a physics problem okay of course

play03:37

physics uses calculus all the scientists

play03:40

use calculus as the mathematics the more

play03:42

you know when you study them at a higher

play03:44

level but we're going to basically find

play03:47

the maximum of a shape right and i'm

play03:49

going to do that in just one second but

play03:51

let's kind of emphasize why this is so

play03:53

unique now if you've taken algebra you

play03:55

might recognize this shape here

play03:58

as a parabola okay it's a parabolic

play04:01

shape and we can just use

play04:03

some other algebraic techniques to find

play04:06

what we call uh the vertex right which

play04:09

is this point up here

play04:11

okay which is the maximum but i'm going

play04:13

to show you how we can use calculus to

play04:15

find this point as well because this is

play04:17

a nice illustration

play04:19

basic illustration of calculus now in

play04:21

calculus when you learn calculus okay

play04:26

there's pretty much two big primary um

play04:30

concepts that we learn okay big picture

play04:33

topics let's just say the first one is

play04:35

integration okay integration is a little

play04:38

symbol like this you've probably seen

play04:39

this before

play04:41

looks kind of crazy like so

play04:44

and let's suppose this was on the xy

play04:46

chart right here integration uh

play04:50

is

play04:51

basically um the way we can find area

play04:54

underneath the curve with something okay

play04:58

so very very powerful i've not done a

play04:59

few videos on the basics of calculus so

play05:02

we learned integration then we learned

play05:04

this other thing uh

play05:06

called the derivative okay the

play05:08

derivative kind of looks like this

play05:10

symbol dx d y

play05:12

or y prime there's all kinds of ways you

play05:14

can uh it's expressed okay but we learn

play05:19

about the derivative so there's like a

play05:21

big huge topic and calculus is the

play05:24

derivative and then we also learn about

play05:26

integration okay in this particular

play05:28

problem we're going to be using this

play05:29

concept here the derivative uh and the

play05:32

derivative more or less okay

play05:35

let's kind of erase all this stuff here

play05:38

the derivative allows us to find

play05:41

the slope okay the derivative has to do

play05:44

conceptually with the slope of something

play05:47

so here's my little curve my little

play05:49

parabola

play05:51

and along this parabola let's say at

play05:53

this point right here what's the slope

play05:56

of this parabola well it would kind of

play05:58

be like

play05:59

this line like right here right

play06:01

that would be the slope but what

play06:03

precisely is the slope of the parabola

play06:06

at this point

play06:07

well that's where we need calculus okay

play06:10

but let's just kind of follow this uh

play06:13

parabola around and let's just study

play06:15

what the slope is looking like how about

play06:16

this point right here well at that point

play06:19

the slope might be something like this

play06:21

right

play06:22

okay so we can see the slope is changing

play06:25

along this parabola how about this point

play06:27

right here

play06:28

well the slope is like well maybe like

play06:31

this and we kind of drew it kind of bad

play06:34

something like that now

play06:35

this

play06:36

line okay is what we call a tangent line

play06:40

it just this is one line that just

play06:42

touches at one single point that

play06:45

parabola at these uh precise points so

play06:48

this

play06:49

these lines are going to touch at that

play06:50

one point now here this would not be the

play06:52

case but i'm just kind of sketching

play06:54

around here trying to make a

play06:56

bigger point now

play06:58

if you don't know basic algebra

play07:01

when we talk about the slope we're

play07:03

talking about the angle of something

play07:04

right the steepness of something here

play07:06

so the slope in this direction

play07:08

we indicate that by this little variable

play07:11

m

play07:12

is going to be positive okay so slopes

play07:14

that run like this way increase from

play07:17

left to right is a positive slope uh

play07:20

slopes that go down this way are the

play07:22

negative slope so what do you think a

play07:24

line that goes this way what's the angle

play07:26

of this line how steep is this line okay

play07:28

this is a horizontal line

play07:30

you might be saying that it has no slope

play07:32

it's zero and you would be correct okay

play07:35

so lines that are flat okay or

play07:37

horizontal okay have zero slope i'm

play07:40

going to erase this here in a second

play07:42

okay so these lines horizontal lines

play07:46

have zero slope and vertical lines here

play07:50

their slope is what we call undefined we

play07:52

don't really need to get into that for

play07:53

this particular um

play07:55

video but just so you know

play07:58

if i'm trying to find the maximum point

play08:00

just think of it

play08:01

as a roller coaster this is probably

play08:03

good

play08:04

uh representation here you are going up

play08:06

a roller coaster you're increasing okay

play08:08

so positive slope is like you're

play08:09

increasing on your roller coaster and

play08:11

then right here at the very very top

play08:13

you're like flat right you're perfectly

play08:16

horizontal you are like this okay the

play08:19

slope is zero

play08:22

then you go down the other side roller

play08:24

coasters are so cool

play08:25

okay

play08:26

and now we have negative slope okay so

play08:29

this is where the slope is negative this

play08:31

is where the slope is positive and right

play08:33

here on the top when everyone is just

play08:35

like scared scared scared and then

play08:37

they're like oh and you kind of go back

play08:39

down this is this one point right there

play08:43

okay

play08:44

is the top okay of the roller coaster

play08:47

the top or the maximum okay

play08:50

of

play08:51

of the

play08:52

this parabola and that's what we're

play08:54

trying to determine now again

play08:57

if you studied algebra there's other

play09:00

techniques but this is a basic simple uh

play09:03

parabola okay

play09:05

there could be more challenging

play09:06

techniques that algebra can help us out

play09:08

and we're going to have to use our

play09:10

friend calculus okay so we're going to

play09:12

be using the derivative to

play09:15

determine the maximum of this parabola

play09:17

so let's get into it now

play09:19

okay

play09:20

so here is our problem okay we want to

play09:22

find the maximum now this particular

play09:25

function here okay its graph is not

play09:27

exactly this just kind of drew this to

play09:29

make it look kind of interesting

play09:31

so here is

play09:33

this graph this graph's really more like

play09:35

this on the x y plane so here's our

play09:37

function

play09:38

and if i was to graph this parabola it

play09:40

would be like so okay but again i'm

play09:43

trying to find

play09:45

this maximum point right there now

play09:48

that's also known as the vertex we want

play09:50

to find this maximum point okay where

play09:52

does this thing max out now

play09:55

as i indicated we're going to use this

play09:59

concept here

play10:00

called the derivative and this is the

play10:03

notation we want to find the first

play10:06

derivative of this function okay

play10:08

so this is the notation again d x d y it

play10:11

looks like this and

play10:13

again you don't need to know a lot about

play10:15

it just know

play10:16

that we're going to find the first

play10:18

derivative okay now

play10:20

let's this is the the function when i

play10:23

find the first derivative

play10:25

d x d y

play10:27

okay or

play10:28

f prime okay this right here this is

play10:31

actually the first derivative i'm gonna

play10:32

find i'm gonna show you how i got got to

play10:34

this what does that mean when i find the

play10:37

derivative okay this function right here

play10:40

its graph is this parabola here is the

play10:44

parabola this thing right here is the

play10:46

graph of that parabola when i find the

play10:49

first derivative okay these are all

play10:52

equivalent

play10:53

notations i could write it as d x d y

play10:56

uh or i could write it like this now

play10:58

notice i said the first derivative i

play11:00

could find the second derivative that

play11:02

means something in more advanced

play11:04

mathematics especially like physics and

play11:06

stuff but i don't want to digress too

play11:08

much because i could just get overly

play11:10

excited about calculus it's such a cool

play11:11

topic but anyways here's the deal

play11:15

when i find the first derivative of this

play11:17

function

play11:18

here's the function here's its graph

play11:20

when i find the first derivative it's

play11:22

going to give me a formula for the slope

play11:26

okay

play11:27

so the first derivative is a formula for

play11:30

the slope of anywhere along this line

play11:33

this is actually the first derivative

play11:35

okay

play11:36

so

play11:37

i'm going to show you precisely what

play11:39

this means so this is going to give me a

play11:40

derivative a

play11:43

formula for the slope or m okay now

play11:46

remember we talked about a roller

play11:48

coaster m is positive here

play11:50

m is zero right there okay and then m is

play11:54

negative right there so what i'm going

play11:56

to want to find is where is the slope

play11:59

equal to 0 okay remember we just talked

play12:02

about that because that is going to be

play12:04

the top of this parabola where where the

play12:06

slope is 0

play12:07

is going to be

play12:08

where uh the maximum okay point is on

play12:12

this parabola

play12:13

all right so how do we find the first

play12:16

derivative okay so that's what it means

play12:19

so here is how we find the first

play12:20

derivative so

play12:21

in uh calculus we're given a bunch of

play12:23

rules not that difficult just kind of

play12:26

algebraic manipulations but

play12:28

here is our polynomial function our

play12:31

little quadratic equation if you've

play12:33

taken enough algebra to understand so

play12:35

here's what we're going to do okay to

play12:37

find the first derivative we're going to

play12:40

take this thing is written in highest

play12:42

power to lowest power we take this

play12:44

little exponent right there okay here

play12:46

let's kind of make it bigger

play12:48

negative

play12:50

x

play12:50

squared okay

play12:52

so we're going to take the 2

play12:55

i'm going to multiply by that number

play12:56

that's a negative 1 okay so it's going

play12:59

to be i'm sorry we're going to take i'm

play13:00

sorry you're going to be take the 2 or

play13:02

multiply by that negative

play13:04

number which is this one okay so two

play13:06

times negative one

play13:08

is negative two

play13:10

all right so take that little two

play13:12

whatever the exponent might be if it was

play13:13

three i would multiply by three so take

play13:15

the two multiply

play13:16

by this number that's negative one x

play13:18

squared so 2 times negative 1 is

play13:21

negative 2. then i'm going to take that

play13:23

same variable x i'm going to write it

play13:25

like so okay and then whatever this

play13:27

power is it was 2 i'm sorry it is 2. i'm

play13:31

going to decrease it by 1.

play13:33

so that would be just to the first power

play13:35

one okay

play13:37

let me do that again all right so we can

play13:40

understand this rule to take have a

play13:42

functional polynomial function to be

play13:44

able to find the first derivative it's

play13:46

not that difficult so we have negative x

play13:50

squared okay

play13:52

i take the 2

play13:53

multiply by this number which is just a

play13:55

negative 1. 2 times negative 1 is

play13:58

negative 2.

play14:00

it's the variable x now whatever this is

play14:02

i'm going to drop it down by 1. so

play14:04

that's 2 to the first or just 2. okay i

play14:07

could write it just like that and that

play14:09

is step one okay now i'm going to do the

play14:12

same thing

play14:13

over here

play14:14

all right so what's the power of this

play14:16

it's 1

play14:18

okay so it's going to be

play14:20

1 times negative 8

play14:22

is what

play14:23

negative 8 times x 2

play14:26

this is 1. i'm going to drop it down by

play14:29

one

play14:30

so that's x to the zero

play14:32

anything to the zero power is one

play14:35

anything to the zero power is one so

play14:38

that's really negative eight times one

play14:40

so

play14:41

my first derivative is negative two x

play14:45

minus eight because it's negative eight

play14:47

times one this is really just one and

play14:49

then

play14:51

when you're taking the derivative of a

play14:52

number it's just zero it goes away okay

play14:55

so this here

play14:57

is our first derivative again i'm using

play14:59

different notation

play15:01

here it's the function x okay f of x

play15:05

so

play15:05

all equivalent notation what we just

play15:08

found is the first derivative of this

play15:09

function f so it can be

play15:12

written as d x d y very very common okay

play15:16

or we could write this little apostrophe

play15:18

that's the first derivative of the

play15:20

function f or this function's name is f

play15:23

i can write it like this okay all

play15:25

equivalent f prime we would call this

play15:27

okay f prime first derivative of this

play15:30

function again this is a lovely formula

play15:34

for the slope okay it's going to tell me

play15:36

where the slope is at now i'm interested

play15:38

in

play15:39

where is the slope equal to zero okay

play15:42

remember

play15:43

okay

play15:44

just a quick review the slope is

play15:45

positive in this direction

play15:47

its slope is negative in this direction

play15:49

but at this one precise point at the top

play15:52

of the roller coaster the slope is zero

play15:54

all right so let's find that point now

play15:56

okay

play15:57

erase all of this

play16:01

okay so

play16:02

here is my

play16:04

formula for my slope i know my slope

play16:07

along this function along this parabola

play16:09

is equal to negative two x

play16:12

minus eight so i'm gonna i wanna say to

play16:14

myself okay mr slope where are you equal

play16:17

to zero because that's where i'm

play16:19

interested in knowing okay where the

play16:21

slope is equal to zero so i'm going to

play16:22

set the slope

play16:24

the formula

play16:26

uh or the equation here for the slope

play16:28

equal to zero and i'm gonna solve

play16:30

that equation so negative two x

play16:33

minus eight equals zero i'm going to

play16:35

move the 8 over to the other side of the

play16:37

equation that's negative 2x

play16:39

is equal to 8 and i'm going to divide

play16:42

both sides equation by negative 2

play16:44

so x is equal to negative 4 okay

play16:48

so right here um one two three four

play16:52

negative four

play16:53

along where x is negative four at this

play16:56

point

play16:57

that is the maximum

play17:00

along the x-axis of where that's at and

play17:03

if i wanted to know this exact

play17:04

coordinate i would just plug in negative

play17:06

4

play17:07

into my original function and i actually

play17:10

just did that right here

play17:12

okay let's plug in negative 4 into our

play17:14

original function to find out what the

play17:16

y-coordinate is and when i do that

play17:18

whoops

play17:19

you can see here

play17:21

i'm plugging in very precisely negative

play17:23

4 here i do all the math and f of

play17:25

negative 4 for this function is 7.

play17:28

so the top of that parabola okay right

play17:32

there okay it's located we have one two

play17:35

three four negative four

play17:37

seven okay seven this way all right not

play17:41

negative seven

play17:42

but seven

play17:43

in this direction right there so that

play17:46

vertex that maximum point for this

play17:48

parabola occurs at negative 7

play17:50

4. now

play17:52

uh this is an illustration of using the

play17:55

first derivative okay of a function

play17:59

all right to solve a problem now there

play18:01

is another way more direct approach we

play18:04

can use algebra but this is a an easy

play18:07

problem okay uh algebra can you know

play18:09

help us with the easy problem but then

play18:11

there's a lot of other things that

play18:12

calculus just you know cannot help us

play18:14

with all right we

play18:16

you know but i you know chose this

play18:18

because this is our first calculus

play18:19

problem together i wanted this to make

play18:21

sense uh to you and hopefully even if

play18:24

you didn't get all the algebraic

play18:26

manipulations and i think um hopefully

play18:28

you can understand the concept of the

play18:30

roller coaster stuff here and get an

play18:33

appreciation for the basic main basic

play18:37

concepts of calculus integration

play18:39

and uh the derivative right now

play18:42

again you know i'm oversimplifying a lot

play18:46

of things and if you have you know a

play18:48

pretty advanced math uh background you

play18:49

might say hey you missed that you missed

play18:51

this yes listen i get that right i'm not

play18:53

trying to teach a full calculus course

play18:55

here that's just the point

play18:56

of this video the point is to teach you

play18:59

a little something about the subject of

play19:01

calculus so you can appreciate it and

play19:03

maybe even

play19:05

get motivated enough excited about

play19:07

enough to be like you know what i want

play19:08

to learn this uh subject okay it's

play19:11

definitely

play19:12

uh

play19:13

a great goal you might be like yeah well

play19:15

you're a math teacher you love math of

play19:17

course you're going to like want

play19:18

everyone to know calculus i'm like yeah

play19:20

well it is

play19:22

people just don't realize okay without

play19:24

calculus

play19:25

um

play19:26

all our modern day technology would just

play19:28

fall apart right calculus has solved

play19:32

so many problems uh technical problems

play19:34

we just would not be here without

play19:37

calculus we wouldn't have our cell

play19:38

phones we wouldn't have uh airplanes

play19:41

yadda yadda yadda okay anyways i don't

play19:43

want to

play19:44

start preaching here about a calculus

play19:46

importance of it but it's just a

play19:47

fascinating mathematics subject and it

play19:49

does take you know it is a serious

play19:52

subject you do have to really build up

play19:53

your math skill sets uh to be prepared

play19:56

to actually take an informal way but i

play19:58

think that would be a noble goal for

play20:01

sure well if you found this video

play20:03

entertaining interesting in some way

play20:05

or helpful uh definitely appreciate you

play20:08

smashing that like button that helped me

play20:10

out and uh if you're new to my youtube

play20:12

channel hopefully you'll consider

play20:13

subscribing i actually have hundreds and

play20:15

hundreds of math videos been on youtube

play20:16

for a long time

play20:18

obviously i love teaching math so have a

play20:20

lot of uh videos already organized in

play20:22

various playlists there to help you out

play20:25

uh so you can just go to my channel

play20:26

check things out but i'm posting stuff

play20:28

all the time all types of various of uh

play20:31

level of mathematics but if you want my

play20:32

best help definitely follow

play20:35

the links in the description of this

play20:37

video but with that being said i

play20:38

definitely wish you all the best in your

play20:40

mathematics and adventures thank you for

play20:42

your time and have a great day

Rate This

5.0 / 5 (0 votes)

関連タグ
Calculus BasicsMath EducationDerivativesIntegrationMath HelpAlgebra SkillsParabolaMaximum AltitudeRoller CoasterMathematics
英語で要約が必要ですか?