Euler method is coming up wrong? Help?

I have the following equation: (x^3)y' + 20*(x^2)y = x with y(2)=0
I have to get the Euler code to run and execute. So far this is my code, but the graph looks wrong, and the approximations aren't even showing up. Any ideas why this may be happening?
Script file:
function[T,Y] = euler(f,a,b,ya,h)
a = 0; b = 1;
T = a:h:b;
Y = zeros(1,length(T));
Y(2) = ya;
for k = 1 : length(T)-1
Y(k+1) = Y(k) + h*f(T(k),Y(k));
end
Code:
%%Part 1 - Euler
% y'(t) = 3*y(t)
% A function file euler.m is needed; you'll do this in the homework
clear all
% define the problem: function f and domain
f = @(t,y) (1/(t^2)) - ((20*y)/t);
a = 2; b = 10;
% exact solution, using a fine grid
t = a:.0001:b;
y = (1./(19.*t)) - (524288./(19.*(t.^20))); % this is a vector of values, not a function
% coarse solution
h = .01;
ya = 0;
[T1,Y1]=euler(f,a,b,ya,h);
% fine solution
h = .001;
ya = 0;
[T2,Y2]=euler(f,a,b,ya,h);
% finer solution
h = .0001;
ya = 0;
[T3,Y3]=euler(f,a,b,ya,h);
plot(t,y,'k',T1,Y1,'bo-',T2,Y2,'ro-',T3,Y3,'go-')
legend('Exact','h=0.01','h=0.001','h=0.001')
title('The Euler Method with 3 meshes')

댓글 수: 1

Geoff Hayes
Geoff Hayes 2016년 2월 17일
Kaylene - please don't create a duplicate of previously asked questions (<http://www.mathworks.com/matlabcentral/answers/268698-any-ideas-why-euler-method-isn-t-running>).

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이 질문은 마감되었습니다.

질문:

2016년 2월 17일

마감:

2016년 2월 17일

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