Q.Evaluate $\displaystyle\int \frac{dx}{9-x^{2}}$.

Fixed results for denominators of the type $x^{2}\pm a^{2}$: $\int\frac{dx}{x^{2}-a^{2}}=\frac{1}{2a}\log|\frac{x-a}{x+a}|+c$, $\int\frac{dx}{a^{2}-x^{2}}=\frac{1}{2a}\log|\frac{a+x}{a-x}|+c$, $\int\frac{dx}{x^{2}+a^{2}}=\frac{1}{a}\tan^{-1}\frac{x}{a}+c$, $\int\frac{dx}{\sqrt{x^{2}\pm a^{2}}}=\log|x+\sqrt{x^{2}\pm a^{2}}|+c$, and $\int\frac{dx}{\sqrt{a^{2}-x^{2}}}=\sin^{-1}\frac{x}{a}+c$. Identi …