Sine wave generator?

Could you please teach me how to create sine waves with arduino due. I have to create 2 of them. One of frequency 33kHz and 1 of 8kHz? Could you guide me through please.

You can start from this code:

There is perhaps a simpler starting point for understanding the concepts: http://arduino.cc/en/Tutorial/DueSimpleWaveformGenerator

try this one

https://www.youtube.com/watch?v=-hKIXj5dAjc