Question

Решите уравнение
cos^2x + sin2x=0

Answer 1

$cos^{2}x+sin2x=0\\cos^{2}x+2sinxcosx=0 |:cos^{2}x\\1+2tgx=0\\2tgx=-1\\tgx=- \frac{1}{2}\\x=-arctg \frac{1}{2}+\pi n,n\in Z$