Question

СРОЧНО НУЖНА ПОМОЩЬ!!!

Answer 1

Ответ:

$1+tg^2t=1+\dfrac{sin^2t}{cos^2t}=\dfrac{cos^2t+sin^2t}{cos^2t}=\dfrac{1}{cos^2t}=(cost)^{-2}\\\\\\\\1+ctg^2t=1+\dfrac{cos^2t}{sin^2t}=\dfrac{sin^2t+cos^2t}{cos^2t}=\dfrac{1}{sin^2t}=(sint)^{-2}$