capacitance

Monsu

You are given a low pass filter of 50nF and a resistor of 100 KOhm.
a) Draw the circuit diagram;
b) Calculate the 3dB frequency;
c) Calculate the impedance of the series circuit of R and C and draw it in the complex plane at
about 2 decades around the 3dB point and at the 3dB point.
d) Draw the circuit diagram for a high pass filter with same components.


I am asked to calculate the 3db freq, right? is this the right formula f = 1 / (2piRC) ?
and afterwards calc the impedance z = R + jXc where Xc = 1 / (2pifC) ?
and then getting the decades, say our freq was 31.8Hz , 2 decades below would b 0.318? 2 decades above would b 3180?
then we should use those values of f to determine the Xc at those frequencies, and then find z at each of these frequencies?
then we plot a graph showing all the z's?


pls smne help me coz i'm totally confused!!!
thanks in advance!