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Proving Operating Functions

  1. May 6, 2009 #1
    1. The problem statement, all variables and given/known data

    If P(x)=x^(1/2)
    show that P(x+h)-P(x)=h/[(x+h)^(1/2)+ x^(1/2)]

    2. Relevant equations



    3. The attempt at a solution


    pls help me. I don't have any idea of this...
     
  2. jcsd
  3. May 6, 2009 #2

    Cyosis

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    Homework Helper

    Try multiplying by:

    [tex]\frac{\sqrt{x+h}+\sqrt{x}}{\sqrt{x+h}+\sqrt{x}}[/tex]
     
  4. May 6, 2009 #3
    Will i going to substitute it on the x variable? I don't know where it needs to be multiplied.
     
  5. May 6, 2009 #4

    HallsofIvy

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    Staff Emeritus
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    "Multiply" doesn't mean substitute!

    First form P(x+h) by replacing x with x+ h. Then subtract P(x) from that. That's what "P(x+h)- P(x)" means! Cyanosis is suggesting that you can get the final form you want by multiplying by
    [tex]\frac{\sqrt{x+h}+\sqrt{x}}{\sqrt{x+h}+\sqrt{x}}[/tex]
     
  6. May 7, 2009 #5
    tnx for the explanation. :)
     
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