Question

поможіть ..............​

Answer 1

Ответ:

$\sin {}^{2} (x) \times {\ctg}^{2} (x) + \cos {}^{2} (x) = \\ = \sin {}^{2} (x) \times \frac{ \cos {}^{2} (x) }{ \sin {}^{2} (x) } + \cos {}^{2} (x) = \\ = \cos {}^{2} (x) + \cos {}^{2} (x) = 2 \cos {}^{2} (x)$