Question

Спростити

(1+tg^2 a)+1/sin^2 a

(1-ctg a)^2+ (1+ctg a)

Answer 1

$frac{1}{cos^{2} alpha}+frac{1}{sin^{2} alpha}= frac{sin^{2} alpha+cos^{2} alpha}{sin^{2} alpha*cos^{2} alpha} = frac{1}{sin^{2} alpha*cos^{2} alpha}$ = $frac{4}{ sin^{2} 2 alpha }$