关于Matlab微分方程求解问题

Question

求该题答案，自己写的代码老是报错。希望可以有人能指点指点，万分感谢

Answer 1

解析

syms y z x;
[y z]=dsolve('Dy-z=sin(x)','Dz+y=1+x','y(0)=2','z(0)=7','x');
vpa(y)
vpa(z)

数值

% y 是y(1)  z是y(2)
f = @(x,y)[sin(x)+y(2);1-x-y(1)];
[x,y]=ode45(f,[0,200],[2;7]);

plot(x,y(:,1));
hold on;
plot(x,y(:,2));
grid on;