Find the exact value of cos(u + v) ) given that sin u= 9/41 cos nu=- 15/17 . (Both u and v are in Quadrant II.)

Answer 1

in QII
sinu = 9/41
cosu = -40/41
cosv = -15/17
sinv = 8/17
cos(u+v) = cosu cosv - sinu sinv
so plug in your numbers

Answer 2

Answer: cos(u+v)=528/697