前向欧拉法、后向欧拉法、梯形方法、改进欧拉方法MATLAB

function [x, y] = Trapezium(f, y0, a, b, h) y(1) = y0; n = (b - a)/h; x = a:h:b; for i=1:n yt = y ( i ) + h * feval ( f, x ( i ), y ( i ) ); done = 0; while ~done y ( i + 1 ) = y ( i ) + 0.5 * h * ( feval ( f, x ( i ), y ( i ) )+feval ( f, x ( i+1 ), yt ) ); done = ( abs ( y ( i + 1 ) - yt ) < 1e-6 ); yt = y ( i + 1 ); end end