If cot(x)= -16/15, where x is in quadrant IV, what is the exact value of sin(2x)?

2 answers

tan(x) = 1 / cot(x) = -15 / 16

sin(2x) = [2 tan(x)] / [ 1 + tan^2(x)]
nice one, but why not be even more direct?

sin(2x) = [2 cot(x)] / [ 1 + cot^2(x)]

amazing, innit? Just multiply top and bottom by cot^2(x)