How can I derive the period of oscillation for a relaxation oscillator?

[limofunder]

Homework Statement

I am having a bit of trouble with a homework problem on relaxation oscillators, the schematic is shown below:

https://webspace.utexas.edu/sz233/Relaxation%20Oscillator.png

The original problem states:
derive a relationship for the period of oscillation for a relaxation oscillator in terms of R1, R2, RC, V_CC
and V_EE.

Homework Equations

So I know from E&M that
V=IR, and C=Q/V.
also, I know that dq/dt = I

The Attempt at a Solution

from this, I deduce, possibly erroneously, that
V_- = IR +\frac{1}{C} \int I(t)dt
so
0 = R \frac{dI}{dt} + \frac{1}{C} * I(t)
then
\frac{dI}{I} = - \frac{1}{RC} dt
it follows that
I = I₀Exp[-t/RC]

given that current doesn't change at the + or - poles on the amplifier, then this should be the same current that goes through V₊ thus using the voltage divider formula,
V_out = V_+ * \frac{R_2}{R_1 + R_2}
Now, how do I relate the V_out here with the current from above?

 

[limofunder]

Is there a reason for which the latex code doesn't appear? I pulled the notation direct from the sigma reference in the tool box menu

 

[limofunder]

thanks a bunch guys