2021-007

Choose the incorrect alternative below:

1. If $f(x)=2x^{-2}$, then $f^{\prime }(x)=-4x^{-1}$
2. If $f(x)=x{e}^x$, then $f^{\prime }(x)=(x+1)e^x$
3. If $f(x)=\sqrt{x^2+1}$, then $f^{\prime }(x)=x/\sqrt{x^2+1}$
4. If $f(x)=x^{-1}$, then $\int 𝑓=\ln x+C$
   
5. none of the above

Original idea by: Mauricio Schiezaro