Question

Cos square 13 minus sin square 77

Answer 1

$cos {}^{2} 13 + sin {}^{2} 77 \\ = cos {}^{2} 13 + sin {}^{2}(90 - 13) \\ = cos {}^{2} 13 + cos {}^{2}13 \\ = 2cos {}^{2} 13$
Please mark as brainliest....✔✔✔

Answer 2

HEY MATE HERE IS YOUR ANSWER :

cos²13+sin²77

=cos²13+sin²(90−13)

=cos²13+cos²13

=2cos²13

HOPE THIS MAY HELP YOU ✌️