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?

Pre-Calculus 4.2: Trigonometric Functions and the Unit Circle part

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

trigonometry - Why does sin(90)=1, and not 0? - Mathematics Stack

c# - I understand that Sin and Cos are in radians, but why I am

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

Unit Circle: Sine and Cosine Functions · Precalculus

Summary: The Unit Circle and Trigonometric Functions