Question

evaluate sin square 13 degrees - cos square 77 degrees​

Answer 1

Answer:

We have : sin^2 13° - cos^2 77°

=>sin^2 13° - cos^2 (90°-13°)

=>sin^2 13° - sin^2 13°. [cos(90°-a) = sin a]

=>0

Here is you answer

Answer 2

Answer:

$= sin(13) - cos(77) \\ = cos(90 - 77) - cos(77) \\ = cos(77) - cos(77) \\ = 1 \\ hope \: this \: help \: uuuu$