how to get this expression from the circuit

[nhrock3]

it is given that R1=R2

http://i43.tinypic.com/b8359w.jpg
i used voltage divider
i tried to calculate it by taking v1 as the midle poit of the left brench
and v2 as the middle point of the of the other branch

so Vout=V_s/2 -Vs[r/(r+1/jwc )=v_s/2(1-rjwc/2(rjwc+1))

i cant get the expression in the photo

[berkeman]

it is given that R1=R2

http://i43.tinypic.com/b8359w.jpg
i used voltage divider
i tried to calculate it by taking v1 as the midle poit of the left brench
and v2 as the middle point of the of the other branch

so Vout=V_s/2 -Vs[r/(r+1/jwc )=v_s/2(1-rjwc/2(rjwc+1))

i cant get the expression in the photo

I get the expression in the photo, so it must just be an algebra problem in your work. Be careful with your parenthesis when writing it out like you did above... the last expression is missing some parenthesis that make a difference.

In Latex:

V_o = V_s (\frac{1}{2} - \frac{R}{R + \frac{1}{jwC}})

V_o = V_s (\frac{1}{2} - \frac{R}{\frac{jwRC}{jwC} + \frac{1}{jwC}})

... and so on ...