mathmari Posted April 23, 2013 Share Posted April 23, 2013 Hi!!! I need some help...I want to write a code in matlab for the backward euler method.How can I solve the equation to determine y^(n+1)??? Are newton's method, fixed point iteration, fsolve, fzero equal??? Link to comment Share on other sites More sharing options...
mathmari Posted April 26, 2013 Author Share Posted April 26, 2013 To use Newton's method, do i have to write:for i=1:ny(n+1)=y(n)-(g(y(n))/dg(y(n));where g=y(n+1)-y(n)-h*f(t(n+1),y(n+1)) ??? Link to comment Share on other sites More sharing options...
elfmotat Posted April 27, 2013 Share Posted April 27, 2013 (edited) For the backward Euler's method, you could use something like the following: clc; clear; ti=0; tf=10; n=5000; h=(tf-ti)/n; t(1)=ti; y(1)=1; for i=1:n dydt=sin(t(i)); t(i+1)=t(i)+h; y(i+1)=y(i)+h*dydt; end; plot(t,y) I used dy/dt=sin(t) as an example function. To make it go backwards, all you have to do is make tf<ti, so that h becomes negative. Edited April 27, 2013 by elfmotat Link to comment Share on other sites More sharing options...
mathmari Posted April 28, 2013 Author Share Posted April 28, 2013 Ok... Thank you very much!!!! Link to comment Share on other sites More sharing options...
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