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alffer1
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Hi all! Need serious Multivariable Calc help. Right now we're learning practical applications of double integrals: An annulus with inner radius r=1 and outer radius r=2 has density equal to delta(x,y)=3*(y+sqrt(x^2+y^2))/pi. Compute the mass of the annulus using polar coordinates. I get an answer, but I'm almost sure it's wrong.
 10 months ago
 10 months ago
alffer1 Group Title
Hi all! Need serious Multivariable Calc help. Right now we're learning practical applications of double integrals: An annulus with inner radius r=1 and outer radius r=2 has density equal to delta(x,y)=3*(y+sqrt(x^2+y^2))/pi. Compute the mass of the annulus using polar coordinates. I get an answer, but I'm almost sure it's wrong.
 10 months ago
 10 months ago

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Vivek3461 Group TitleBest ResponseYou've already chosen the best response.0
The transformation from Rectangular/Cartesian coordinate to Polar coordinate is given by the substitution x=r.cos (theta) and y = r.sin (theta), where x,y are from cartesian coordinate and r, theta are from polar coornidate. r  Radial distance from centre ( range of is from 1 to 2 for this problem ) Theta  angle measured counterclockwise wrt positive xaxis ( 0 to 2.pi for this problem) So to find the mass find the following, dw:1391528427817:dw V is the volume. But for the given problem the annular portion's thickness information is not given. So kindly cross check the problem statement. Or else assume unit thickness and proceed. :)
 9 months ago
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