If cos theta is = -3/5 and of pi < theta 3 pie/2 then sin theta is what?

Question

I don’t know how to solve this question.

Answer 1

If cos θ = -3/5 then sin θ = ±4/5 depending upon in whether θ is in quadrant 3 or 4...and I think your question means that θ is in quadrant 3 which mean yo should choose the - value.