Question

Упростите выражение:

Answer 1

$1-sin^2\alpha-cos^2\alpha = -(sin^2\alpha+cos^2\alpha)= cos^2\alpha-cos^2\alpha = 1-1 = 0$

$1 + tg^2\alpha - \frac{1}{cos^2\alpha} =1 + \frac{sin\alpha}{cos\alpha} - \frac{1}{cos^2\alpha} = \frac{cos^2\alpha+sin^2\alpha - 1}{cos^2\alpha} = \frac{1-1}{cos^2\alpha} = \frac{0}{cos^2\alpha} = 0$