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September 20th, 2015, 11:13 AM  #1 
Newbie Joined: Sep 2015 From: illinois Posts: 2 Thanks: 0  Euler Lagrange formula
I'm having some trouble trying to figure out the Euler's equations for some differential equations, I have the answer but I'm not sure how the professor is getting them. I know you're suppose to use ∂F/∂yd/dx(∂F/∂y'=0) but I can't get the partial derivatives and such right to match up the answer. Problems Answer 1st: y'' +16y = 0 Answer 2nd: 1 +2y''=0 
September 20th, 2015, 11:24 AM  #2 
Newbie Joined: Sep 2015 From: illinois Posts: 2 Thanks: 0 
I figured out the second one: ∂f/∂y = 0 ∂f/∂y'=x+2y' d/dx(∂f/∂y') = 1+2y'' but one the second I'm not quite getting the answer: ∂f/∂y = 2y'32' ∂f/∂y'= 2y'+2y d/dx(∂f/∂y') = 2y''32 = 0 Any ideas? 

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euler, formula, lagrange 
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