from r to R e^(-2r/a)*r^2 dr
U're one lazy dude... :yuck: Two times part integration,pay attention to signs and integration limits.
Looks pretty standard to me.
Use "integration by parts", twice.
If you let u= r2 and dv= e-2r/a, then du= 2r dr and
v= -a/2 e-2r/a
Now you have an integral of e-2r/ar and integrating by parts again will give you an integral with just e-2r/a.
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