thanks in advance

- What value of coupling capacitor is required in the figure so that the signal voltage at the input of amplifier 2 is at least 70.7% of the signal voltage at the output of amplifier 1 when the frequency is 20Hz ?

i know the answer the cap must be: 0.0796 microF

but i cant find a way to achieve that

what I'm doing is to use the voltage divider formula, (r1/r1+Xc)Vs = vs * 70.7%

and solve for Xc i use a sample voltage of 2v source , then i use the xc = 1/(2)(pi)(f)© and solve for c, but my answer is totally wrong.

thanks for your help and please excuse my poor english.