Question

Упростите выражение (1-cos^2x)/(cos^2x-cos2x)

Answer 1

$\frac{1-cos^2x}{cos^2x-cos2x}= \frac{sin^2x}{cos^2x-(cos^2x-sin^2x)}= \\ \\ = \frac{sin^2x}{cos^2x-cos^2x+sin^2x}= \frac{sin^2x}{sin^2x}=1$