Question

Срочно!!!!! Помогите

Answer 1

Ответ:

$1)f(x)=\sqrt{6x+7}\\ f'(x)=\frac{1}{2}(6x+7)^{-\frac{1}{2}}*6=\frac{3}{\sqrt{6x+7}}\\ f'(3)=\frac{3}{\sqrt{6*3+5}}=\frac{3}{5}$

$2)f(x)=(cosx)^4\\f'(x)=4cos^3x*(-sinx)=-4sinx*cos^3x\\f'(\frac{\pi }{4})=-4*sin\frac{\pi }{4}*cox^3\frac{\pi }{4} =-4*\frac{\sqrt{2}}{2} *(\frac{\sqrt{2} }{2})^3=-1$