Question

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

Answer 1

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