How does the signal look when we don't use the Nyquist rate to remove aliasing from a signal during sampling?

Let's suppose the signal is sinusoidal, with a frequency of 500&nbsp;Hz and an amplitude of 2.

signal = 2*cos(2*pi*500*t)


If I sample it, (replacing t=nTs , Ts = sampling period and n represent number of samples) and plotting the sampled signals with a different sampling period using the subplot command in MATLAB, how could I identify the aliasing in a sampled signal?

Here is the example code that plotted two signals, one at the Nyquist rate while the other less than the Nyquist rate:

A = 2;
Fmax = 10;
Fs = 2*Fmax;
n = 0:1/Fs:1;
Cont = A*sin(2*pi*(Fmax/Fs)*n);
Cont1 = A*sin(2*pi*(Fmax/18)*n);
subplot(2,1,1)
stem(n,Cont)
hold on
stem(n,Cont1)


and here is the waveform:



I wasn't able to identify the aliasing. How did it affect the signal when Nyquist rate didn't use?


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Answer: I do this exact thing with an external drive. Same basic idea as the new partition without repartitioning. I have never looked into the nuts and bolts but the drive is on when you boot up so shows up for everyone and we use it for any data that is appropriate to share between users.