Help with an integral

  • Thread starter eoghan
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  • #1
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Hi there!
I have to calculate the integral of the function sqrt(x^2+y^2) over the circle (x-1)^2+y^2<=1

I use polar coordinates: rho goes from 0 to 2cos(theta) and theta goes from 0 to 2pi.
My result is that the integral is 0... is it right?
 

Answers and Replies

  • #2
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Yea I did it and got 0 because you end up integrating [itex]\cos(\theta)^3[/itex] at the end, which is 0.
 
  • #3
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eohgan, if you think about what the geometric meaning of the integral is, it should be clear as to why your answer is zero.
 
  • #4
tiny-tim
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Hi there!
I have to calculate the integral of the function sqrt(x^2+y^2) over the circle (x-1)^2+y^2<=1

I use polar coordinates: rho goes from 0 to 2cos(theta) and theta goes from 0 to 2pi.
My result is that the integral is 0... is it right?
Hi eoghan! :smile:

erm … doesn't theta go from -π/2 to π/2? :redface:
 

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