Question

What is the reference angle of sin(-45)?

Answer 1

Assuming you mean `-45` radians, the reference angle is `14pi - 45`

`45 -: 2 pi ~~ 7.16` and

`14 pi ~~ 43.98`

So, to get `-45` that only leaves about `-1.02` which is a 4th quadrant angle with reference angle `1.02`.

The exact value is `14pi - 45`