Question

- 10/(1 + cot^2 alpha) - 10cos^2 alpha Найдите решение ​

Answer 1

Объяснение:

$\displaystyle\\-\frac{10}{1+ctg^2\alpha } -10*cos^2\alpha =-\frac{10}{1+\frac{cos^2}{sin^2\alpha } }-10*cos^2\alpha } =-\frac{10}{\frac{sin^2\alpha +cos^2\alpha }{sin^2\alpha } } -10*cos^2\alpha =\\\\\\=-\frac{10}{\frac{1}{sin^2\alpha } } -10*cos^2\alpha =-10*sin^2\alpha -10*cos^2\alpha =-10*(sin^2\alpha +cos^2\alpha )=-10.$

Ответ: 4) -10.