Posted by billy on .
give the exact real number value without using a calculator
sin[(cos^1)(1/4)]
sin[(tan^1)(3/4)+(tan^1)(12/5)]

trig 
bobpursley,
On each of these, draw the triangle. On the first, the adjacent side is 1, the hyp is 4, so the opposite side is sqrt(161) So sine of that angle is sqrt15/4
Same idea on the next.