Question

I know a) is -1, but I am not sure of b).

Answer 1

Simplify the trigonometric function.

`\begin{gathered} \sin (270^(\circ))=\sin (90^(\circ)+180^(\circ)) \\ =\cos (180^(\circ)\text{)} \\ =-1 \end{gathered}`

The other trigonometric function is cosine and angle is 180 degree.