Question

Упростить sin 2a (1+tg^2a)

Answer 1

1+tg^2a=1 + sin^a / cos^2 a = (cos^2a +sin^2 a)/ cos^2a = 1/cos^2a
sin2a=2sinacosa
2sinacosa/cos^2a = 2 sina/cosa=2tga