can anyone explain the equation sin(fπx) where f is a sound wave's frequency in Hz. I am trying to convert sound waves into graphed sine waves by using their frequency but don't understand the formula. Why are we multiplying by π? If anyone knows another equation to graph the sound like a sine wave I would be very grateful... I found this equation online and it doesn't seem right...

Can anyone explain the equation $\sin(fπx)$ where $f$ is a sound wave's frequency in Hz?

I am trying to convert sound waves into graphed sine waves by using their frequency but don't understand the formula. Why are we multiplying by $\pi$? 

If anyone knows another equation to graph the sound like a sine wave I would be very grateful... I found this equation online and it doesn't seem right...