Hi,

I want to get an expand an expression of the form and finally get the rhs of the below expression

\begin{align}
\Big(\frac{A1*{a}}{r}+\frac{A2*{a}}{r^{2}}\Big)\Big(\frac{B1*{a}}{r}+\frac{B2*{a}}{r^{2}}\Big)=\frac{A1*{a}B1*{a}}{r^{2}}+\frac{A1*{a}B2*{a}+A2*{a}B1*{a}}{r^{3}}+\frac{A2*{a}B2*{a}}{r^{4}}
\end{align}

For this i used the following code

$ch3:=((A0*{a}/r)+(A0*{a}/r**2))((B0 {a}/r)+(B0{a}/r**2));$

$distribute(ch3);$

$simplify(_);$

But finally i am getting the expression
\begin{align}
A1*{a}B1*{a}r^{-1}r^{-1}+A1*{a}B2*{a}r^{-2}r^{-1}+A2*{a}B1*{a}r^{-2}r^{-1}+A2*{a}B2*{a}r^{-2}r^{-2}
\end{align}

It is not simplifying after this to get the rhs of the expression i wanted in the beginning. I have just shown a simple expression for the convenience of expressing my doubt. The actual expression is pretty large.

It would be helpful if the mistake I am doing can be pointed out and how to simpify the mathematical expressions.