Implicit differentiation

  • Thread starter dankelly08
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  • #1
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so I have a implicit diffentiation problem and was wondering if someone could help me out.. I need to figure out how to get

dy/dx=0

so eg if i had

dy/dx = 4xy+2x/5y^2

and you want to write this in terms of y, how is this done? is there a trick?
 

Answers and Replies

  • #2
arildno
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Well, if dy/dx is to be 0, it follows that:
[tex]x(4y+\frac{2}{5y^{2}})=0[/tex]
Having as possible solutions that either x=0, or [tex]y=-\frac{1}{\sqrt[3]{10}}[/tex]
 
  • #3
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thanks for your help, but im still not too sure how this works so how about with this example

1-2x/4+2y = 0
 
  • #4
arildno
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Well, then along the line y=x/4-1/2, dy/dx will equal zero.
 
  • #5
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ah right thanks, its just i'm trying to figure out in my notes what steps my lecturer took to get x=1/2.. and i cant see how he's done it..
 

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