b) \( f(x)=\ln \left(\frac{1}{x^{2}}\right) \)
\( f´(x)=\frac{1}{\frac{1}{x^2}}*(\frac{0*x^2-1*2x}{(x^2)^2})=x^2*(-\frac{2x}{x^4}) =x^2*(-\frac{2}{x^3})=-\frac{2}{x}\)
c)\( f(x)=\frac{x+1}{\sqrt{x}} \)
\( f´(x)=\frac{1*\sqrt{x}-(x+1)*\frac{1}{2*\sqrt{x}}}{x}\)=\( \frac{\sqrt{x}-\frac{x+1}{2*\sqrt{x}}}{x} \)=\( \frac{\sqrt{x}*2*\sqrt{x}-x-1}{x*2*\sqrt{x}} \)=\( \frac{2x-x-1}{2x*\sqrt{x}} \)=\( \frac{x-1}{2x*\sqrt{x}} \)