Calculus Calculus Math Forum

 June 25th, 2016, 06:57 PM #1 Senior Member   Joined: May 2012 Posts: 205 Thanks: 5 Euler Lagrange I'm looking at the Euler-Lagrange equation derivation, df/dy-d/dx(df/dy')=0 In the derivation, they treat the the original integral, int(f(y',y,x)dx) like a regular calculus max/min problem, that is, they take the derivative with respect to some 'variance', while keeping the limits of the integral the same, and set it to zero, and from there make their way to the Euler-Lagrange equation... the goal being to find the conditions such that y(x) is the shortest path between two points. The variance is defined by a new function, Y(x) = y(x) + εg(x), where I take it that ε takes on arbitrary real numbers of multiplied by an arbitrary function g(x). I don't understand how this all really works and why we can treat the problem like a calculus problem, I don't even know enough to ask the right questions to help me understand it better.... What can I learn that will ultimately help me understand this? Last edited by skipjack; June 26th, 2016 at 12:53 AM. June 26th, 2016, 12:55 AM #2 Global Moderator   Joined: Dec 2006 Posts: 21,128 Thanks: 2337 What book or article are you using? June 27th, 2016, 12:01 PM #3 Senior Member   Joined: May 2012 Posts: 205 Thanks: 5 This wasn't originally what I was looking at, but its the same derivation: Derivation of the Euler-Lagrange-Equation — Martin Ueding Thanks from manus Tags euler, lagrange Thread Tools Show Printable Version Email this Page Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Similar Threads Thread Thread Starter Forum Replies Last Post bb2921 Differential Equations 1 September 20th, 2015 12:24 PM KeyserSoeze Calculus 0 May 6th, 2014 08:36 AM muzialis Calculus 0 May 1st, 2012 11:18 AM FalkirkMathFan Calculus 1 November 5th, 2011 01:57 AM FalkirkMathFan Real Analysis 0 November 4th, 2011 05:08 AM

 Contact - Home - Forums - Cryptocurrency Forum - Top      