Evaluate the following integrals.

a$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{1}{x^2}-\sqrt[3]{x^4}+4dx$

b$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}{e}^{4x}+3sin(3x)-\frac{2}{x}dx$

Evaluate the following integrals using u$-$substitution.

a$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}x{e}^{4x^2}dx$

b$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}4x^{3}cos(x^4)dx$

c$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{2ln(x)}{x}dx$