Music and Math

a single Note, such as C4, as frequency of a string (as f=1), its double frequency C5 (1 octave higher note, f=1/2) is the frequency of half length of the same string.

we can define: 2/3 length of that C4 string is G4, (which is a note in-between C4 and C5, f=2/3)

then, start from G4, as frequency of a new string, 2/3 of that length, we get D5 (f=2/3 * 2/3 = 4/9), so if we start with C3 as 2, then D4 = 2*4/9 = 8/9

then, same circle of C4, G4, D5, A5 continues