Matlab HIgh frequency sine wave generation
The function you need to evaluate is:

A*sin(2*pi*FREQUENCY*(1:NUM_SAMPLES)/SAMPLE_RATE)


Use a reasonable sample rate (at least twice the frequency) and a reasonable interval (remember that at a sample rate of 2Ghz, 1 second of signal will fill up the memory of your computer) ; and it'll work! From your code it seems that you are trying to generating 100s of signal at a sample rate of 1kHz, which doesn't make sense.

At the moment, in your code, the argument of the sin function is an integer multiple of $2\pi$ so in theory your code should be plotting a flat line of 0s. You are seeing something a bit different due to the finite resolution of floating point numbers.