How to use mathematical physics method (numerical method)?

First, the theoretical solution is to use the dsolve function (enter doc dsolve in the command window to view help).

Example:

Code:

[x，y]= dsolve(' D2x+2 * Dx = x+2 * y-exp(-t)'，' Dy=4*x+3*y+4*exp(-t)')

Second, the numerical solution, using ode45, or ode23, ode 15s and other functions. (enter doc ode45 in the command window to view help. )

Example:

1. Create M file

Function dy=vdp(t, y)

dy =[y(2)；

1000*( 1-y( 1)^2)*y(2)-y( 1)； ];

2. Call MATLAB function ODE 15S.

[T，Y]=ode 15s('vdp '，[0 1000]，[2 0])；

plot(T，Y(:， 1))；

The image is: