第六题的二价微分方程可以用matlab的ode()函数命令来求解。求解过程如下:
y0=[2,3];
[t,y]=ode45(@odefun,[0 10],y0); %odefun自定义微分方程函数
figure(1)
plot(t,y),grid on
legend('y(t)','dy/dt')
xlabel('t'),ylabel({'y(t)','dy/dt'})
figure(2)
plot(y(:,1),y(:,2)),grid on
xlabel('y(t)'),ylabel('dy/dt')
title('y(t) 与 dy/dt 相平面图'
运行结果的图形
![](https://iknow-pic.cdn.bcebos.com/a50f4bfbfbedab646522fa69fb36afc378311ec2?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)