Question

cos a/1-sin a+cos a/1+sin a помогите пожалуйста...

Answer 1

$frac{cos alpha }{1-sin alpha } + frac{cos alpha }{1+sin alpha } = frac{cos alpha (1+sin alpha )+cos alpha (1-sin alpha )}{1- sin^{2} alpha } = frac{2cos alpha }{ cos^{2} alpha } = frac{2}{cos alpha }$