Question

If cos theta is equal to 5 upon 13 then cos 2 theta is equal to

Answer 1

Answer:

cos(2θ) = -119/169

Step-by-step explanation:

Given cos theta = 5/13

We use the identity,

$\cos(2x) = 2\cos^2(x) - 1$

=> cos(2θ) = 2cos²(θ) - 1

=> cos(2θ) = 2(5/13)² - 1

=> cos(2θ) = 50/169 - 1

=> cos(2θ) = 50-169/169

=> cos(2θ) = -119/169

This your answer.