- #1
tnmann10
- 2
- 0
I am not understanding integration with polar coordinates, or at least visualizing what is happening. Here's the integral calculated in Wolfram:
http://www.wolframalpha.com/input/?i=integrate+(r^2(cost^2-sint^2))r+drdt+t=(0)..(pi/2)+r=(1)..(2)+
the integral before I changed it to polar was just ∫R(x2-y2)dA where R is the first quadrant region between the circles of radius 1 and 2
mathematically it makes sense that the answer is 0.
but when you draw the picture it is a quarter of a washer in the xy plane. This does not seem like 0 to me. Would someone please explain where my thinking is going wrong?
Thanks
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http://www.wolframalpha.com/input/?i=integrate+(r^2(cost^2-sint^2))r+drdt+t=(0)..(pi/2)+r=(1)..(2)+
the integral before I changed it to polar was just ∫R(x2-y2)dA where R is the first quadrant region between the circles of radius 1 and 2
mathematically it makes sense that the answer is 0.
but when you draw the picture it is a quarter of a washer in the xy plane. This does not seem like 0 to me. Would someone please explain where my thinking is going wrong?
Thanks
First post