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Theelectricchild
Apr10-04, 10:12 PM
Hello.

Here is the original question http://phasedma.com/uploaded/TripleIntegral.JPG (http://)

My difficuly is understanding the limits of integration--- party due to how the solid in question is "sliced" by those planes. I know how to visualize the parabolic cylinder, but I need help on 1. limits on integration, and 2. Order of integration.

I doubt I would have to use polar coordinates since the region in question has no square roots...

Thanks for you help I really do appreciate this.

Theelectricchild
Apr10-04, 10:13 PM
Arghh that links not working, just copy paste it into the url. Sorry.

outandbeyond2004
Apr10-04, 10:25 PM
TEChild, you can use Latex coding here, click on this link:
http://physicsforums.com/showthread.php?t=8997

\int \int \int_E (x + 2y)dV

where E is bound by the parabolic cylinder

y=x^2

and the planes

x=z,x=y,z=0

outandbeyond2004
Apr10-04, 11:10 PM
Divide and conquer. z appears as an independent variable once and as a constant. So, easy to eliminate x:

\int _E ()dV = \int_0^1 dz \int dy \int_z^1 ()dx

Do you see why the upper limit on z is 1? Solve the innermost integral as tho y and z were constants.

Theelectricchild
Apr10-04, 11:27 PM
actually I dont see why the upper limit on z is one... thats where I was confused --- I understand why it starts at 0 of course... and also the y limits are giving me trouble...

outandbeyond2004
Apr11-04, 12:24 AM
taking z as the independent variable, ask yourself: what is the greatest z value a point in the bounded volume can have?

Theelectricchild
Apr11-04, 12:31 AM
ahhhh i got it thanks so much

Divergent13
Apr11-04, 04:41 AM
Ooh Bellingham--- are you a graduate student at Western Washington U. outandbeyond?