A'Rieka - Repérage dans le plan

Summary

This video explains how to locate points on a coordinate plane using the concepts of abscissas (x-axis) and ordinates (y-axis). It introduces a mnemonic to help remember the process: first, move along the street (abscissa) and then up or down the floors (ordinate). The video walks through the steps to determine a point's coordinates, including examples to demonstrate the method. By understanding these steps, users will easily grasp how to pinpoint any point in a 2D plane by referencing its horizontal and vertical positions.

Takeaways

• 😀 The lesson focuses on understanding how to locate points on a coordinate plane using specific coordinates (abscissa and ordinate).
• 😀 The coordinate system consists of two axes: the abscissa (horizontal axis) and the ordinate (vertical axis). Both axes intersect at the origin.
• 😀 To locate a point, its coordinates (abscissa and ordinate) need to be given, similar to navigating a street and floor in a building.
• 😀 The abscissa is the horizontal component (like the street), while the ordinate is the vertical component (like the floor level).
• 😀 To find a point's abscissa, you move horizontally along the abscissa axis. To find the ordinate, you move vertically along the ordinate axis.
• 😀 The mnemonic method compares finding coordinates to navigating through a building: first find the street (abscissa), then determine the floor (ordinate).
• 😀 When a point is on one of the axes (e.g., on the x-axis or y-axis), one of its coordinates will be zero. For example, a point on the x-axis has an ordinate of 0.
• 😀 The first step in locating a point is to find its abscissa, then the ordinate. Both coordinates are necessary to uniquely define a point's position.
• 😀 If a point's abscissa is negative, it is located to the left of the origin on the x-axis, and if the ordinate is negative, it is below the origin on the y-axis.
• 😀 The script provides examples using specific coordinates (e.g., (-3, 8) and (0, -3)) to demonstrate how to locate points based on given coordinates.

Q & A

What are the two axes in a coordinate plane?

The two axes in a coordinate plane are the abscissa (horizontal axis) and the ordonnée (vertical axis).

What is the significance of the origin in a coordinate plane?

The origin is the point where the abscissa (x-axis) and the ordonnée (y-axis) intersect, and both coordinates at the origin are zero.

What is the first coordinate of a point called, and what does it represent?

The first coordinate of a point is called the abscissa, and it represents the point's position along the horizontal axis (x-axis).

What is the second coordinate of a point called, and what does it represent?

The second coordinate of a point is called the ordonnée, and it represents the point's position along the vertical axis (y-axis).

How do you plot a point on a coordinate plane using its coordinates?

To plot a point, first move along the horizontal axis (abscissa) to the x-coordinate, then move vertically along the y-axis (ordonnée) to the y-coordinate.

Can you describe the mnemonic used in the lesson to remember the plotting process?

The mnemonic suggests thinking of a street and floors: 'First walk along the street (abscissa), then go up or down the floors (ordonnée)'.

What should you do if the abscissa of a point is negative?

If the abscissa is negative, move to the left along the horizontal axis (x-axis) by the absolute value of the coordinate.

How does the lesson suggest plotting the point (−3, 8)?

To plot the point (−3, 8), move 3 units to the left along the horizontal axis and then 8 units up along the vertical axis.

What is the procedure for plotting the point (0, -3)?

For the point (0, -3), you stay on the vertical axis (since the abscissa is 0) and then move 3 units down along the vertical axis (ordonnée).

What is the key concept to remember when giving the coordinates of a point?

The key concept is that the first coordinate (abscissa) tells you how far along the horizontal axis the point is, and the second coordinate (ordonnée) tells you how far along the vertical axis the point is.