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Homework Help: D3y/dx3 OF Y= 1/X+1

  1. Nov 11, 2007 #1
    1. The problem statement, all variables and given/known data
    d3y/dx3 OF Y= 1/X+1


    2. Relevant equations

    Y= 1/X+1

    3. The attempt at a solution

    i TRIED USING THE QUOTIENT RULE BUT BECAME STUCK AFTER DOING- (X+1)D/DX(1) + (1)D/DX(X+1)= (X+1)(1)+(1)(1)=1+1+1= 3 BUT HOW DO GET TO THE THRID DEGREE IM LOST
     
  2. jcsd
  3. Nov 11, 2007 #2

    rock.freak667

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    Homework Helper

    [tex]y=\frac{1}{x+1}[/tex]

    [tex]\frac{dy}{dx}=\frac{1(x+1)-1(1)}{(x+1)^2}[/tex]

    [tex]\frac{dy}{dx}==\frac{x}{(x+1)^2}[/tex]
    then just differentiate that twice again and you'll get [itex]\frac{d^3y}{dx^3}[/itex]
     
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