When someone plays the piano, the sound is beautiful and you can use maths to describe the sound. A simple equation is y = sin t (time). But this equation would give you a pure note that lasted for ever. To vary the frequency (f) otherwise known as pitch you need to change the equation to y = sin (ft). As the frequency increases so does the pitch of the note, to increase the note by 1 octave you need to double the frequency. To vary the amplitude (A) on top of the frequency you need to change the equation to y = A sin (ft). As the amplitude gets bigger, the note gets louder. Finally, to change the volume as time goes on you need to use a formula that goes like y = A(t) sin (ft).
