# Need help with this integral!

## Main Question or Discussion Point

int((z-r*x)/[z^2+r^2-2*z*r*x]^(3/2), x)

cristo
Staff Emeritus
Is this the integral you want to solve? $$\int\frac{z-rx}{(z^2+r^2-2zrx)^{3/2}}dx$$

Last edited:
arildno
Homework Helper
Gold Member
Dearly Missed
Would that be:
$$\int\frac{z-rx}{\sqrt[\frac{3}{2}]{z^{2}+r^{2}-2zrx}}dx$$

sure, i made the substitution u=z^2+r^2-2zrx, but got since du/dx=2zr and i was unable to cancel the x on top. also i let u =(z^2+r^2-2zrx)^3/2, i was unable to solve it. I tried maple, mathworld integrator but was unable to get an answer. I did that so i could at least see what direction to go in. Don't want the solution straight out but help on what direction to go would be great. I know it can be solved using Legendre polynomials but I want to solve it without use of that technique.

Is this the integral you want to solve? $$\int\frac{z-rx}{(z^2+r^2-2zrx)^{3/2}}dx$$

ps- how are you posting this mathematical notation? I am young but eager so please be patient with me guys.

cristo
Staff Emeritus