Chapter 8.8, Problem 90E

Making an Integral Improper For each integral, find a nonnegative real number b that makes the integral improper. Explain your reasoning.

${\displaystyle \int \begin{array}{c}b\\ 0\end{array}}\frac{1}{x^2-9}dx$ ${\displaystyle \int \begin{array}{c}b\\ 0\end{array}}\frac{1}{\sqrt{4-x}}dx$

${\displaystyle \int \begin{array}{c}b\\ 0\end{array}}\frac{x}{x^2-7x+12}dx$ ${\displaystyle \int \begin{array}{c}10\\ b\end{array}}\text{ln}xdx$

${\displaystyle \int \begin{array}{c}b\\ 0\end{array}}\tan 2xdx$ ${\displaystyle \int \begin{array}{c}b\\ 0\end{array}}\frac{\cos x}{1-\sin x}dx$