MATLAB: Second order ODE diff

diff second order odeMATLAB

Hello,
I have this second order ODE for damped oscillator. Easy way to solve it would be using ODE45 but I need to use MATLAB function 'diff' to obtain velocity and acceleration.
syms x(t) sin(t)
eq(t)=diff(x,t,t)+0.78*diff(x,t)+14*x==0.56*sin(t*147);
vel=diff(eq,t);
acc=diff(eq,t,t);
I've got to this point so far. But I can't work out what to do next or even if I'm on the right track.
Thanks

Best Answer

syms x(t)
eqn=diff(x,t,2)+0.78*diff(x,t)+14*x==0.56*sin(t*147);
xsol(t)=dsolve(eqn);
vel(t)=diff(xsol,t)
acc(t)=diff(xsol,t,2)