Anonymous
Anonymous asked in Science & MathematicsMathematics · 1 month ago

Points on a unit circle ?

What are the points that lie on a unit circle for the following angles?

1. 220 degrees

2. 120 degrees

3. 7π/4

4. 5π/9

Please teach me the answers and the way to find it.

2 Answers

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  • 1 month ago

    The point's x coordinate is the cosine of the angle, and the point's y coordinate is the sine.

    So, (cos 220, sin 220)

    (cos 120, sin 120)

    Cos 7π/4, sin 7π/4)

    etc.  If it's one with an exact value, you could simplify.  Like, you know sin 120 = (√3)/2 and cos 120 = - 1/2 

    so #2 would become (-1/2 , √3 / 2)

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