Question

Упростите: cos a * tg a * sin a - 1

Answer 1

Ответ:

$\cos( \alpha ) \times tg( \alpha ) \times \sin( \alpha ) - 1 = \\ = \cos( \alpha ) \times \frac{ \sin( \alpha ) }{ \cos( \alpha ) } \times \sin( \alpha ) - 1 = \\ = \sin {}^{2} ( \alpha ) - 1 = - (1 - \sin {}^{2} ( \alpha )) = - \cos {}^{2} ( \alpha )$