Question

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

Answer 1

Answer:

  $\left(\dfrac{1}{2},-\dfrac{\sqrt{3}}{2}\right)$

Step-by-step 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)