Question

If theta is in quadrant 2 and cos theta = -3/4, find an exact value for sin 2 theta?

Answer 1

what are the signs for cosine and sine on the 2nd quadrant?

Answer 2

No idea, that's the only thing the question says.

Answer 3

well, check your Unit Circle

Answer 4

recall that \(\bf cos(\theta)=\cfrac{x}{radius}\qquad sin(\theta)=\cfrac{y}{radius}\) and that the radius is always positive

Answer 5

Well what I did so far was this