I have read from Savant's book, this equation that allow to calculate the capacitor from a demodulator:

I've tried to calculate my circuit with this equation, but it didn't work, so then I tried to recalculate this example from the book, but I dont know what is 'w' here in the example:

" A 15Mhz radio frequency carrier is modulated with a 5kHz signal with a modulation index (m) of 0.5. If the load resistance is 5 kOhms, what capacitor value must be added in parallel to the load to filter the radio frequency signal?

response: 0.013 uF "

¿Can you please teach me how to obtain w, to calculate C?, I tried with 15Mhz, and 5kHz, but I don't get the same answer.

thank you.