www.gusucode.com > matlab 案例源码 matlab代码程序 > matlab/twobodyode.m
function dy = twobodyode(t,y) % Two body problem with one mass much larger than the other. r = sqrt(y(1)^2 + y(3)^2); dy = [y(2); -y(1)/r^3; y(4); -y(3)/r^3];