Double integral problem
(attachment below)
I am unable to figure out how to solve r*root(1+r^2 /4) within the dr integral :S

Any help would be much appreciated! (Just the method to solve it should be enough) :)

Question

Double integral problem
(attachment below)
I am unable to figure out how to solve r*root(1+r^2 /4) within the dr integral :S

Any help would be much appreciated! (Just the method to solve it should be enough) :)

anonymous · Answer

attachment

anonymous · Answer

I was thinking product, but It seems too complicated to be so

ganeshie8 · Answer

have you tried u-substitution ?

anonymous · Answer

Yes

ganeshie8 · Answer

u = 1+r^2/4

works smoothly right ?

anonymous · Answer

Tried that, but I can retry it - in case I did it wrong

ganeshie8 · Answer

u = 1+r^2/4


du = ?

anonymous · Answer

Thanks! It worked :) I somehow messed up the du part. I was trying to get du on one side, and saw the dr part didnt match, when I should have gotten dr alone to replace it instead @.@