fft - Plotting magnitude and phase for frequency spectrum

I would like to find the frequency spectrum by drawing magnitude and phase for the following signal:

S=sin(2*pi*100*t)+cos(pi*500*t);

X=sinc(2*pi*t);

Is there something particular to this problem that I should be noticing?

We can easily find the spectra giving a time domain like

t=0:0.01:0.1;

And using the fft command for both signals

X=fft(S);

What did they mean by drawing the magnitude and phase?