$6\mathrm{.}3\mathrm{.}1$ Exercises

Evaluate the following integrals:

$2.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{1}{x^2\sqrt[\phantom{2}]{x^2-9}}dx$

$3.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}{e}^x\sqrt[\phantom{2}]{1+e^{2x}}dx($use the substitution $e^x=tan)$

$4.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{x^4}{\sqrt[\phantom{2}]{25-x^2}}dx$