Question

formula of cos²A+cos²B

Answer 1

there is no such formula.It can be written as follows...
$\cos {}^{2} (a) + { \cos {}^{2} b} = ( \cos \: a + \cos \: b) {}^{2} - 2 \cos \: a \cos \: b$

Answer 2

Answer:

If you know do it or don't do it