Question

4. At what coordinates does the terminal side of a -420° angle intersect the unit circle?

Answer 1

`\left((1)/(2),-(√(3))/(2)\right)`

Explanation:

An angle is co-terminal with the same angle that has any multiple of 360° added to it.

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The angle -420° is co-terminal with (-420° +720°) = 300°. The attached unit circle chart shows the coordinates of the terminal side of that angle.

These coordinates are ...

(x, y) = (cos(300°), sin(300°))

(x, y) = (1/2, -√3/2)