matlab小白求助，如何解微分方程組？

clear all

clc

f=@(t,x)([320*pi*cos(x(2)+8*pi*t)/(178*sin(x(2)-x(1)));

320*pi*cos(x(1)-8*pi*t)/(76*sin(x(1)-x(2)))]);

[t X]=ode45(f,[0 pi/20],[1/2/pi 52/2/pi]);

dx1=320*pi*cos(X(:,2)+8*pi*t)./(178*sin(X(:,2)-X(:,1)));

dx3=320*pi*cos(X(:,1)-8*pi*t)./(76*sin(X(:,1)-X(:,2)));

d2x1=diff(dx1)./diff(t);

d2x3=diff(dx3)./diff(t);

figure(1)

plot(t,X(:,1),t,X(:,2)),legend('x1','x3')

figure(2)

plot(t,dx1,t,dx3),legend('dx1/dt','dx3/dt')

figure(3)

plot(t(1:length(t)-1),d2x1,t(1:length(t)-1),d2x3),legend('d^{2}x1/dt^{2}','d^{2}x3/dt^{2}')