Please help Assume that sin S 725 cos S 2425 sin T 1517 a

Assume that sin S = 7/25, cos S = 24/25, sin T = 15/17, and cos T = 8/17. Find the given quantity without using a calculator. Enter the exact answer. cos (S - T) =

Solution

Remember that cos(X - Y) = cosX cosY + sinX sinY

Putting values in this equation and putting X=S and Y=T

We get 0.2047