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I have a question regarding trignometry

How does Sin(180°-θ) = Sinθ
and how does Cos(180°-θ) = -Cosθ

User Forth
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1 Answer

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Explanation:

If A is acute, cos (180 - A) = - cos A (because the coordinates would be in 2nd quadrant)

If A is right angle, cos (180 - 90) = cos 90 = 0

(because the coordinates would be on y-axis)

If A is obtuse, cos (180 - A) = + cos A (because the coordinates would be in 1st quadrant)

I have a question regarding trignometry How does Sin(180°-θ) = Sinθ and how does Cos-example-1
User Xavier Climent
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