Question

How for angles between 90 and 180 degrees sin(x) = sin(180 - x)?

Answer 1

Hey!

Because sin is positive in 2nd quadrant which lies from 90° to 180°.
That is why sin(x)= sin(180°-x).
sin(90°)=sin(180°-90°).
sin(90°)=sin(90°)= 1

Hope it helps.