Найти производную h(x) 2 tg x вычислить при h' (-3п/4) Дам 50 б

[latex]h'(x)=2* \frac{1}{cos^2(x)} [/latex] [latex]2* \frac{1}{cos^2( -\frac{3 \pi }{4}) } =2* \frac{1}{cos^2(\frac{3 \pi }{4})} [/latex] [latex]2* \frac{4}{2} =4[/latex]

[latex]h(x)=2tgx \\h'(x)=\frac{2}{cos^2x} \\h'(-\frac{3\pi}{4})=\frac{2}{(cos(-\frac{3\pi}{4}))^2}=\frac{2}{(cos\frac{3\pi}{4})^2}=\frac{2}{(cos(\pi-\frac{\pi}{4}))^2}=\frac{2}{(-cos(\frac{\pi}{4}))^2}= \\=\frac{2}{(-\frac{1}{\sqrt2})^2}=4[/latex]