Transfer function, Laplace Transform

[papkin]

Homework Statement

[PLAIN]http://img340.imageshack.us/img340/8508/circuit.png

Find V2(s)/V1(s) (Laplace transform domain)

Homework Equations

KCL, capacitor equation.

The Attempt at a Solution

$$\frac {-V_2}{R} + \frac {V_1-V_2}{R} + C \frac {d(V_1-V_2)}{dt}=0$$
But in Laplace domain it follows that
$$\frac {V_2 (s)}{V_1 (s)} = \frac {sRC+1}{sRC}$$
and that is apparently incorrect.
Any thoughts on what I did wrong, and what I should do?

Thanks in advance

 

[gneill]

It's a voltage divider. Let z be the impedance of the resistor-capacitor parallel pair. Then

v2/v1 = R/(R + z)

But z = (R * 1/sC)/(R + 1/sC) = R/(1 + sRC)

Therefore,

v2/v1 = (1 + sRC)/(2 + sRC)

 

[papkin]

Sorry, I was actually correct. Forgot about a minus sign in one place. Anyway, thanks for the answer. At least I know that now I have the correct answer.
Cheers.