How do I plot this simple function in matlab

I have a function f(x) = +i x>0;

                       = 1   x=0;

                       = -i  x<0 ;

I am confused because of the existence of the complex number. Suppose I want to take the fourier transform of this function. I do y=fft(f(x)); plot(x,real(y)); Is this right?

Answer 1

[Wayne King]

Did you simply want to plot that complex-valued function of a real variable, f(x), you can do that with stem3

   x= -50:50;
   y = zeros(size(x));
   y(x<0) = -1i;
   y(x>0) = 1i;
   y(x==0) = 1;
   stem3(x,real(y),imag(y))
   xlabel('x'); ylabel('Re(f(x))'); zlabel('Imag(f(x))');

[Poonam]

Hi,

I loved the way you plotted it. Thank you. I would like to know if I could combine the 3 conditions of y and put into one equation. I actually want to multiply this with another function and take the FFT of it? How could I do that?

Answer 2

[Azzi Abdelmalek]

x=rand(100,1) % eg
y=fft(x)
plot(abs(y))

why real(y)?