Question about bvp4c solution

I used bvp4c to solve second order differential equation: A*y'' = f(y), now I want to get some special values from the solutions. How to get the values of y'' and y' from each point?

Answer 1

[Torsten]

If you solved your equation by solving the System

y1'=y2
y2'=f(y)/A,

you can get y' and y'' by

yp=deval(sol.yp,sol.x);
plot(sol.x,yp(1,:),sol.x,yp(2,:));

Here, yp(1,:)=y' and yp(2,:)=y''.

Best wishes

Torsten.

[Jane]

Torsten, thank you very much for your kind help! Sorry to trouble you again, when I use:

    yp=deval(sol.yp,sol.x);

it shows:

Error using deval

must be a structure returned by a differential equation solver.

Error in bvp3

yp = deval(sol.yp,sol.x);

What would be wrong with it?

[Torsten]

You must call deval with the solution obtained by bvp4c.

Thus

sol=bvp4c(...);
yp=deval(sol.yp,sol.x);

Best wishes

Torsten.