Let 0 theta pi2 and sin theta 15 Evaluate cos 2theta Give th

Let 0< theta< pi/2 and sin theta= 1/5

Evaluate cos (2theta) Give the exact answer in the form of fraction.

cos theta=

Solution

0 <theta< pi/2

sin theta = 1/5

theta = arcsin(1/5)

theta = 11.53 degrees

2*theta = 23.07 degrees

cos (theta ) = 0.979795

cos (2 *theta) = cos(23.07) = 23/25