V1 = VsCos(wt)
V2 = VrCos(wt + O)

But, V2 = iR, then

V2 = C (d / dt) (V1 - V2).R

V2 = CR (d / dt) (VsCos(wt) - VrCos(wt + O))

When I derivate, I get this:

Vr = [ Vs*C*W*R*Sin(Wt)] / [ C*W*R* (Sin(Wt + O) - Cos(Wt + O)) ]

Is the above formula correct..??