In music, two notes are said to be an octave apart when one note is exactly twice the frequency of the other. Suppose you have a guitar string playing frequency f0.
A) To increase the frequency by 3 octave(s), to 8f0, by what factor would you have to increase the tension?
B) To increase the frequency by 3 octave(s), to 8f0, by what factor would you have to decrease the length?