什么是三角函数？---**Title:** The Cartesian coordinate system **Textual Information:** The Cartesian coordinate system is named after the French mathematician René Descartes (1596 – 1650). Points in the (x, y) plane are defined by their perpendicular distance from the x- and y-axes relative to the origin, O. The coordinates of a point P are written in the form P(x, y). The x-coordinate, or abscissa, tells us the horizontal distance from the y-axis to the point. The y-coordinate, or ordinate, tells us the vertical distance from the x-axis to the point. **Chart/Diagram Description:** * **Type:** Coordinate plane (Cartesian system). * **Main Elements:** * **Coordinate Axes:** A horizontal line representing the x-axis and a vertical line representing the y-axis. Arrows indicate the positive direction. * **Origin:** The intersection point of the x-axis and y-axis, labeled as O. * **Quadrant:** The top-right region is shaded blue and labeled as "1st quadrant". * **Point:** A green circle (dot) is plotted in the 1st quadrant. * **Coordinates Label:** The text "(5, 3)" is shown below and to the right of the point. This likely represents the coordinates of the plotted point. * **Interactive Elements:** Below the coordinate plane are several icons: a trash bin, a wavy line, a pencil, a highlighter, an undo/redo arrow symbol, and a question mark. These are likely interactive tools within the software presenting this slide. **Other Information:** * **Navigation/Slide Number:** Left arrow button, "3 of 33", Right arrow button. * **Copyright/Source:** © Boardworks Ltd 2005