Non-Inverting Non-Ideal OpAmp Gain

[jnava]

The first part of this problem was to find the gain using an ideal OpAmp.
I am on the second half of this homework problem, where we find Vout/Vin, aka Gain, using a non ideal OpAmp. The attachment is the picture of the circuit.

I know that since the OpAmp is no longer ideal A no longer goes to infinity, which provides a small input on the negative terminal. So, this is what I have right now...but its not getting me to the correct answer...

Vout*(R2 / [R1 + R2]) = Vin + Vout/A


Is this how I would start to find the gain? Once i get Vout/Vin, I could take the lim as A goes to infinity to verify that, the gain equals the ideal OpAmp.

 

[gabbagabbahey]

So, this is what I have right now...but its not getting me to the correct answer...

Vout*(R2 / [R1 + R2]) = Vin + Vout/A

An Op-Amp multiples the difference between the voltage into the positive input and the voltage into the the negative input by its open-loop gain $A$. In other words,

$$V_{\text{out}}=A(V_{+}-V_{-})$$


What are $V_{\pm}$ for the circuit in your diagram?