Question

(1+tg^2a)cos^a

помогите пжлст.:с

Answer 1

$1) 1+ tg^{2} \alpha = 1+ \frac{ sin^{2} \alpha }{ cos^{2} \alpha } = \frac{sin^{2} \alpha +cos^{2} \alpha }{cos^{2} \alpha} = \frac{1}{cos^{2} \alpha}  2) \frac{1}{cos^{2} \alpha} * cos^{2} \alpha = 1$