ONUS: Limit Computation: Evaluating xy/(x^2+y^2) at Origin

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Hi ,
I have difficulty to find the folowing questions about limit computation.
IF lim xy/(x^2+y^2) ( when (x,y)---(0,0))
Evaluate the limit as (x,y) approaches the origin along:
a) The spiral r=0, θ >0
b) The differentiable curve y=f(x), with f(0)=0
c) The arc r=sin(θ )
Thank you
B
 
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brad sue said:
Hi ,
I have difficulty to find the folowing questions about limit computation.
IF lim xy/(x^2+y^2) ( when (x,y)---(0,0))
Evaluate the limit as (x,y) approaches the origin along:
a) The spiral r=0, θ >0
b) The differentiable curve y=f(x), with f(0)=0
c) The arc r=sin(θ )
Thank you
B

ANy help please?
 
Have you tried converting your expression to polar?
 
Have you yet done any work on the problem? There should be at least one thing you can do that is very clear...
 
Hurkyl said:
Have you yet done any work on the problem? There should be at least one thing you can do that is very clear...

Sorry I found out with the polar coordinates.I am ok now Sorry about everything.

B
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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