$($Question $1)15$ points

Evaluate the indicated integrals if $bb$ is a positive real number constant.

A$.{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}tan(\frac{x}{b})dx{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}tan(\frac{x}{b})dx$

B$.{\displaystyle \underset{0}{\overset{b}{}}}\frac{e^{\sqrt[\phantom{2}]{b-x}}}{\sqrt[\phantom{2}]{b-x}}dn{t}_0^{b^{e\sqrt[\phantom{2}]{b-x}}}\frac{\sqrt[\phantom{2}]{b-x}}{\sqrt[\phantom{2}]{b-x}}$

C$.{\displaystyle \underset{0}{\overset{\frac{}{4}}{}}}se{c}^{2}tand{}^{{\displaystyle \underset{\phantom{}}{\overset{\phantom{}}{}}}\frac{}{\text{d}\text{e}\text{c}}}send$