How to get the ceofficients of a expression derived by ODE or integral ? For exampli,C1 and C2 in u

syms rho a b E omega u(r) mu
sigma_r=E/(1-mu^2)*(diff(u,r)+mu*u/r);
sigma_theta=E/(1-mu^2)*(mu*diff(u,r)+u/r);
u=dsolve(diff(r*sigma_r,r,1)-sigma_theta+rho*omega^2*r^2==0)

u = 

Answer 1

[James Tursa]

Typically these would be obtained by combining the solution with initial values for u. Do you have initial values?

[Guoyao.Li]

Thanks!!!

I know that the specific solution for u needs initial conditions,but I want to extract the ceofficients of general solution,which are C1 and C2.And then using ''subs'' in MATLAB to subsitute C1 and C2 with specific value.However,it fails if I directly use syntax "u=subs(u,[C1 C2],[1 2])".

I have tried to use "children" syntax in MATLAB to extract C1 and C2 in u and it succeeds, but I think it's a little tedious.Is there any simple way to do it?