Question

Упростить:
1-cos^2d
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cos^2d-cos2d

Answer 1

$1) frac{1-cos^2 d}{cos^2d-cos2d}= frac{1-1+sin^2d}{1-sin^2d-1+2sin^2d}= frac{sin^2d}{sin^2d}=1$
$2) frac{1-cos^2d}{cos^2d-cos2d}= frac{1-cos^2d}{cos^2d-2cos^2d+1}= frac{1-cos^2d}{-cos^2d+1}=1$