Question

Упростить выражение
tga*ctga+ctg^2a

Answer 1

$frac{sina}{cosa} * frac{cosa}{sina} +ctg^2a =1+ctg^2a=1+ frac{cos^2a}{sin^2a} = frac{sin^2a+cos^2a}{sin^2a} = frac{1}{sin^2a}$