Hi, I'm trying to use 'numeric dsolve' to solve a system of differential equation. dsol:=dsolve(sys,[phi(t),phi1(t),psi(t),psi1(t),theta(t),x(t)],numeric,output=operator) Now I need to substitute the solution obtained for the unknowns into another expression. What would be the best way to do it/ or what should the output format be? Any help or suggestion will be highly appreciated. Thanx, Priya