If you are interested just in the magnitude regardless to the phase, simply let:
y = abs((40*cos(x) + i*54.77*sin(x))./(54.77*cos(x) + i*40*sin(x)));
then plot(x,y)
You can notice that I've used './' to divide numerator by denominator. This means the division will be done element-by-element and not as a matricial form.
hey albbg, thanks for the reply..
Actually I tried .\ and the result was as expected. So what exactly is the difference between ./ and .\
I intend to divide num by denominator only