Question

Решить производную 1) f(x) = √x^3+1 , x = 2 2) f(x) = √x^2 - 2x , x = 3 3) f(x) = x × √x^2 +1 , x = √3

Answer 1

$1)\;f(x)=\sqrt{x^3+1}\\f'(x)=\frac{3x^2}{2\sqrt{x^3+1}}\\f(2)=\frac{12}{2\cdot3}=2\\\\2)\;f(x)=\sqrt{x^2-2x}\\f'(x)=\frac{2x-2}{2\sqrt{x^2-2x}}=\frac{x-1}{\sqrt{x^2-2x}}\\f(3)=\frac2{2\sqrt3}=\frac1{\sqrt3}\\\\3)\;f(x)=x\sqrt{x^2+1}\\f'(x)=\sqrt{x^2+1}+\frac{2x^2}{2\sqrt{x^2+1}}=\frac{x^2+1+x^2}{\sqrt{x^2+1}}=\frac{2x^2+1}{\sqrt{x^2+1}}\\f(\sqrt3)=\frac{2\cdot3+1}{\sqrt{3+1}}=\frac72=3\frac12$