Question

Cos2a + cos2b formula​

Answer 1

Answer:

cos^2A + cos^2B - 2cosAcosBcos(A + B) = sin^2(A + B)

HOPE THIS HELPED U.

Answer 2

Answer:

2 cos ( A+B) cos (A-B)

Step-by-step explanation:

Use the Transformation formula

2 cos ( A+B) cos (A-B)

= $2 cos( \frac{2A+2B}{2} ) cos ( \frac{2A-2B}{2} )$

= 2 cos ( A + B) cos ( A-B )