??? Need help on this question!!! URGENT PLZ!!

Hello there my C++ experts! :)

I need help in doing this question. You guyz have to help me out how to do this question. It is driving me nuts!! I wrote a bit of the code.. and got stuck at the 2nd function.

Here is the question:
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--Operator Overloading--

Design a class Impedance, which contains four data members: an active resistance R, reactive resistance (reactance)  X, impedance magnitude ZM and phase angle θ. The class should use a constructor function to initialize the data members.  

The class should also contain six operator functions to perform the following operations:
1.     Add impedances connected in series and return equivalent impedance    
2.     Add impedances connected in parallel and return equivalent impedance
3.     Change the sign of the reactance
4.     Input an impedance; the user should be able to input an impedance either in
                    rectangular or polar coordinates
5.     Output an impedance in both, rectangular and polar coordinates
6.     Calculate the admittance (i.e. 1/Z)
      
Design the main( ) function, which will test the Impedance class and use all its operator functions.

Note: Z = R+jX, where R is a real part and X an imaginary part of the impedance Z.
        Z(magnitude) = sqrt(R^2 + X^2 )
        Theta = atan(X/R)
        R=Z(magnitude)* cos(theta);
         X=Z(magnitude)* sin(theta);
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Here is my partial code:

#include<iostream>
#include<conio.h>
#include<iomanip>
#include<cmath>
using namespace std;

class Impedance {

private:
        float resistance;
        float reactance;
        float impedance_mag;
        float phaseangle;
public:

Impedance (float r, float reac, float imp, float phase){
resistance =r;
reactance = reac;
impedance_mag = imp;
phaseangle = phase; }

 Impedance operator+(const Impedance &) const;
 Impedance operator*(const Impedance &) const;
 Impedance operator->(const Impedance &) const;

 };

 Impedance Impedance::operator+(const Impedance & i) const //total series IMP.
 {
   Impedance total;
   float real, imag;

   real = resistance + i.resistance;
   imag = reactance + i.reactance;
   total = real + imag;
   return total;
 }

 Impedance Impedance::operator*(const Impedance & j) const//total Parallel IMP
 {
    Impedance total;
    float real, imag, imp_tot1, imp_tot2;
    real = resistance + j.resistance;
    imag = reactance + j.reactance;
    imp_tot1 = sqrt(     ///What do i do here??? damn i am stuck!



}

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I would really appreciate your help.

Thanks
dino.