algebra precalculus - Using unit circle to explain $\cos(0) = 1$ and $\sin( 90) = 1$ - Mathematics Stack Exchange

We have been taught $\cos(0) = 1$ and $\sin(90) = 1$. But, how do I visualize these angles on the unit circle?

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Evaluate the expression without using a calculator. arccos 1/2

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Unit Circle: Sine and Cosine Functions · Precalculus

How is Cos 90°=0, Cos 0°=1 and Sin 90°=1? - Quora

How is Cos 90°=0, Cos 0°=1 and Sin 90°=1? - Quora

3.3 Unit Circle: Sine and Cosine