Convert 7x² + 7y² = 2y to cylindrical coordinates

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Could someone tell me what I'm doing wrong? thanks!

Homework Statement



Write the equation is cylindrical coordinates

7x2 + 7y2 = 2y

r = ? (has to be in the r = ? format)

Homework Equations



r2 = x2 +y2
x = rcos(θ)
y = rsin(θ)

The Attempt at a Solution



7x2 + 7y2 = 2y

7(x2 + y2) = 2y

7(r2 = 2rsin(θ)

r2 = (2rsin(θ))/7

r = sqrt((2rsin(θ))/7)
 

Discussion

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I think it would be better to leave it as [itex]r^2= (2/7) sin(\theta)[/itex] rather than taking the square root, but, yes, that is correct.
 
its an online submission that has r = "enter here" , but i keep getting that its a wrong answer, is there any other way that this could be written?
 
Note that you forgot to cancel out r on both sides of the equation. Don't express r in terms of r in the final answer.
 
Anybody have any idea about tramsforming the momentum equation into 2-D cylindrical co-ordinates...i've already derived the momentum equation from first principle but have difficulty with the transformation to cylindrical co-ordinates
 
Hi, if you have a separate question you should post it in a new thread so that others can aid you. Sometimes people don't bother reading through a thread which already has several replies.