Question

Помогите!!!!

Упростите cos2α- ctg2α/
tg2α-sin 2α

Answer 1

$displaystyle frac{cos^2a-ctg^2a}{tg^2a-sin^2a}=frac{cos^2a-frac{cos^2a}{sin^2a}}{frac{sin^2a}{cos^2a}-sin^2a}=frac{frac{cos^2acdot sin^2a-cos^2a}{sin^2a}}{frac{sin^2a-sin^2acdot cos^2a}{cos^2a}}=\\\=frac{cos^2a(sin^2a-1)}{sin^2a}cdotfrac{cos^2a}{sin^2a(1-cos^2a)}=frac{cos^2acdot(-cos^2a)cdot cos^2a}{sin^2acdot sin^2acdot sin^2a}=\\\=-frac{cos^6a}{sin^6a}=boxed{-ctg^6a}$

Answer 2

Спасибо!!!!!!