cos(x) = \frac{1}{2}\\ x = б\frac{\pi}{3} + 2\pi n,\ n - zeloe " alt="2sin^{2}(x) + 7cos(x)-5 = 0\\ 2(1-cos^{2}(x))+ 7cos(x)-5 = 0\\ 2cos^{2}(x)-7cos(x)+3=0\\ cos(x)_{1,2} = \frac{7б\sqrt{25}}{4} = \frac{7б5}{4}\\ \\ t.k.\ |cos(x)|\leq 1,\ to \ \\ => cos(x) = \frac{1}{2}\\ x = б\frac{\pi}{3} + 2\pi n,\ n - zeloe " align="absmiddle" class="latex-formula">