Cos(x) & Unit Circle - Degrees
- Linda Fahlberg-Stojanovska
In this animation we plot . Here the label and unit on the horizontal is in degrees. There is no unit on the y-axis. The y-value of the cosine function for the angle is the x-coordinate of the point T. (Remember: the y-value of the sine function for this angle is the y-coordinate of the point T.)
Move the slider to α=45°. The . Do you know the exact value of ? Move the slider to α=135°. The . Do you know the exact value of ? Now, let α=–45°. Move the slider to the corresponding angle between 0° and 360°. The . Do you know the exact value of ? Does this agree with the fact that cos(–α)=cos(α)?