Question

помогите пожалуйста) ;( любую задачу​

Answer 1

Объяснение:

$\frac{1 + sinx}{1 + cosx} \div \frac{1 - cosx}{1 - sinx} = \frac{1 + sinx}{1 + cosx} \times \frac{1 - sinx}{1 - cosx} = \frac{1 - {sin}^{2}x}{1 - {cos}^{2} x} = \frac{ {cos}^{2}x}{ {sin}^{2}x } = {ctg}^{2} x$

$\frac{ {cos}^{5}x - {sin}^{4}x \times cosx }{ {cos}^{2}x - {sin}^{2}x} - cosx = \frac{cosx \times ( {cos}^{4}x - {sin}^{4}x)}{ {cos}^{2}x - {sin}^{2}x } - cosx = \frac{cosx \times ( {cos}^{2}x - {sin}^{2}x) \times ( {cos}^{2}x + {sin}^{2}x)}{ {cos}^{2}x - {sin}^{2}x} - cosx = cosx \times 1 - cosx = 0$

$cosx = \frac{1}{2} \\ x = - + arccos \frac{1}{2} + 2\pi \: n \\ x = - + \frac{\pi}{3} + 2\pi \: n$

n€Z