In cos(2000*3.14t) or cos(2000πt)
2πf=ω, where f is the frequency and ω is the angular frequency.
2000π=ω
Let 2000π=2πf
solve for f to find that f=1000 cycles per second or 1 kHz
Assuming that x(t) is a cosine function, Let x(t)cos(2000πt)=cos(1000πt)*cos(2000πt)
This is a combination of 2 different functions, or superposition of waves. In music, the "beat" frequency will either reach a maximum or become 0.
The maximum "beat" frequency will be a-b or 2-1 kHz= 1kHz.
