how to numericaly solve 2 second order homogenous non linear equation in matlab using ode45

Hi every one I want to solve a system of second order ODE equation shown below using ode45.but I have no idea how to solve it.Can anybody help me with that. thanks.

[Yu Jiang]

It seems that the initial condition is exactly the equilibrium of the system. So, the solution would simply be zeros. Can you confirm if the initial condition is correct?