Limit of multi variable func.

  • Thread starter AHMAD MS
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Homework Statement



(x,y)-->(0,0) y*ln (y2+x2)

Homework Equations



!

The Attempt at a Solution


i've tried polar coordinates i end up with sinθ in it don't know how to proceed

and i've taken several paths like y=0 , x=0 , x=y2 , x=y , x=y3
they all yeild zero

Edit : is it right if i after making polar sub. to say that :

r*sinθ * ln r2 [itex]\leq[/itex] r*ln r2
because if its right then problem solved :P
 
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Answers and Replies

  • #2
LCKurtz
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Homework Statement



(x,y)-->(0,0) y*ln (y2+x2)

Homework Equations



!

The Attempt at a Solution


i've tried polar coordinates i end up with sinθ in it don't know how to proceed

and i've taken several paths like y=0 , x=0 , x=y2 , x=y , x=y3
they all yeild zero

Edit : is it right if i after making polar sub. to say that :

r*sinθ * ln r2 [itex]\leq[/itex] r*ln r2
because if its right then problem solved :P
Almost. You need absolute values:

|r*sinθ * ln r2| [itex]\leq[/itex] r*|ln (r2)|
 

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