Posted by Kk on .
Find the exact value of
Sin ( sin1. 9/41  cos1 (5/13)

Pre cal 
Reiny,
let sin1. 9/41 = ß and cos1 (5/13 = Ø
so sin ß = 9/41 and cos ß = 40/41
and cosØ = 5/13 and sinØ = 12/13
then Sin ( sin1. 9/41  cos1 (5/13)
= sin(ß  Ø)
= sinßcosØ  cosßsinØ
= (9/41)(5/13)  (40/41)(12/13) = 525/533