Question

Помогите пожалуйста

Answer 1

$f(x)=\frac{x}{\sqrt{x^2+1}}\\f'(x)=\frac{\sqrt{x^2+1}-x*\frac{2x}{2\sqrt{x^2+1}}}{x^2+1}\\f'(x)=\frac{1}{\sqrt{x^2+1}(x^2+1)}\\f''(x)=\frac{(\sqrt{x^2+1})'(x^2+1)+\sqrt{x^2+1}(x^2+1)'}{(\sqrt{x^2+1}(x^2+1))^2}\\f''(x)=-\frac{\frac{2x(x^2+1)}{2\sqrt{x^2+1}}+2x\sqrt{^2+1} }{(\sqrt{x^2+1}(x^2+1))^2} \\f''(x)=-\frac{\frac{3x^3+3x}{\sqrt{x^2+1} } }{(x^2+1)^3} \\f''(x)=-\frac{3x}{\sqrt{x^2+1}(x^2+1)^2} \\f''(0)=0$