The julia expression of only one equation with two variables

I get one simulation with only one expression below:
the P(t) and Q(t) with their derivative are the expected, all the R,C are known parameters.
suppose the initial values are known ,but I don’t know how to define the ode in julia for using ODEProblem() . please share some suggestions.

I think this is rather a mathematical question than a Julia question, and perhaps a homework question at that? Can you rewrite the equation as a system of equations where the left-hand side only contains therms like \frac{d X(t)}{d t} and the right hand side doesn’t contain time derivatives (i.e. only terms like X(t))? You may need to introduce auxiliary variables. Once you’ve managed that, setting up the ODEProblem should be easier. Good luck!

thanks, I solved it.