Parameters: VTn = 0.75 V, Kn = 2.5 mA/V2, Vdd = 10 V, Vss = - 10 V, RD = 5 kOhm, I1 = I2 = 1.9 mA. Calculate RS to make the gain (Vo/Vi) equal to 5.

My analysis came to:

Av = Vo/Vi = (RD1||RD2)/(Rs+RD1||RD2)

and solving for Rs I got Rs= 2k

It seems like its not the right answer .. any help please?

 

What is VTn?
And if we assume that gm=0, and RD1=RD2 then
Av=Rd/(0.5*Rs) so Rs=2K