What happens to power in spectrum at Nyquist frequency?

I noticed if I produce a sine wave at the Nyquist frequency (1/2 the sample rate) that the power doesn't show up in the spectrum. Here's an example with sample rate = 1024, length of signal = 1024 and frequency = 511.

Things are as they should be. Now with frequency at 512, the Nyqui

st: (not sure why this sentenced got hosed).

Just to complete the demonstration, we'll go t

o 513 Hz.

Aliasing shows up as expected. What happens at 512 Hz, the Nyquist? Where did the power go?

Thanks,

Dan

[dpb]

Think about what a waveform of a signal sampled at exactly Nyquist is...