Question 87
Let $n$ be a positive integer. Simplify
$$\left(\frac{a+a^{-1}b^2}{a-a^{-1}b^2}-1\right)^{-1}\left(b^n(a-b)^{-1}-b^n(a+b)^{-1}\right).$$
For which values of $a,b$ is the expression undefined?
$$\left(\frac{a+a^{-1}b^2}{a-a^{-1}b^2}-1\right)^{-1}\left(b^n(a-b)^{-1}-b^n(a+b)^{-1}\right).$$
For which values of $a,b$ is the expression undefined?