Evaluate Tripple Integral of e^z in Cylindrical Coordinates

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Homework Help Overview

The discussion revolves around evaluating a triple integral of the function e^z using cylindrical coordinates. The region of integration is defined by a paraboloid and a cylinder, specifically z = 1 + x^2 + y^2 and x^2 + y^2 = 5, along with the xy-plane.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the conversion from Cartesian to cylindrical coordinates, examining the limits of integration. There is a focus on ensuring the correct interpretation of the bounds for z, r, and θ.

Discussion Status

Some participants have provided guidance on the limits of integration, questioning the original poster's setup and suggesting corrections. There is acknowledgment of a potential misunderstanding regarding the limits for z, with some clarification offered on the proper bounds.

Contextual Notes

Participants note the importance of correctly defining the limits of integration, particularly for z, and express uncertainty about the integration steps. There is a mention of the need for clarity in the notation used for cylindrical coordinates.

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Homework Statement


Using cylindrical coordinates, evaluate ʃʃʃe^z where E is enclosed by the paraboloid z = 1 + x^2 + y^2 and the cylinder x^2 + y^2 = 5 and the xy-plane.

Homework Equations


The Attempt at a Solution


here are the integrals in xyz coordinates:
0>z>1 + x^2 + y^2
-(5-x^2)^.5 > y > (5 - x^2)^.5
-(5)^.5 > x > (5)^.5

i double checked that with my proffessor so it has to be right. but i must be doing something wrong when i switch into polar coordinates. here is what the polar limits are (i thought):
0 > z > 1 + r^2
0 > r > 5^.5
0 > ɵ > 2pi

i keep getting the wrong answer. if anything is wrong i would think it is z. unless maybe it is right and i am just integrating wrong but i checked over a million times and didnt c any mistakes :( i have:
ʃʃʃ(e^z)rdzdrdɵ

edit: let me know if u need more info. i can type out all my integration steps if u think my limits look good
 
Last edited:
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jaredmt said:
ʃʃʃ(e^z)rdrdɵ


No dz integration? :confused:
 
jaredmt said:

Homework Statement


Using cylindrical coordinates, evaluate ʃʃʃe^z where E is enclosed by the paraboloid z = 1 + x^2 + y^2 and the cylinder x^2 + y^2 = 5 and the xy-plane.


Homework Equations





The Attempt at a Solution


here are the integrals in xyz coordinates:
0>z>1 + x^2 + y^2
You realize this makes no sense don't you? 1+ x2+ y2> 1 for all x, y. z can't be less than 0 and greater than 1! Surely you mean 0< z< 1+ x2+ y2.

-(5-x^2)^.5 > y > (5 - x^2)^.5
-(5)^.5 > x > (5)^.5

i double checked that with my proffessor so it has to be right. but i must be doing something wrong when i switch into polar coordinates. here is what the polar limits are (i thought):
0 > z > 1 + r^2
Again 0< z< 1+ r2

0 > r > 5^.5
0 > ɵ > 2pi

i keep getting the wrong answer. if anything is wrong i would think it is z. unless maybe it is right and i am just integrating wrong but i checked over a million times and didnt c any mistakes :( i have:
ʃʃʃ(e^z)rdrdɵ

edit: let me know if u need more info. i can type out all my integration steps if u think my limits look good
So you have
\int_{r= 0}^{\sqrt{5}}\int_{\theta= 0}^{2\pi}\int_{z= 0}^{1+r^2} e^z dzd\theta dr[/itex]<br /> Is that right?
 
yes that is right. sorry i typed it up wrong, my bad. I am not sure how to use those symbols either but w/e

does the limits look right to u?

edit: i changed it and added dz, should be typed up correctly now

edit: o sorry, actually the same thing u wrote, but multiplied by r. i thought u had to do that when u change to polar. idk maybe it is different in this case for some reason
 

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