Two notes form an octave how are there frequencies related?

Two notes that form an octave have a frequency ratio of 2:1, which means that the higher note's frequency is twice that of the lower note. This relationship can be expressed using the following formula:

$$f_2 = 2f_1$$

where:

- $$f_1$$ is the frequency of the lower note

- $$f_2$$ is the frequency of the higher note

Here is an example of how to calculate the frequency of an octave above a given note:

- If the frequency of the lower note is 100 Hz, then the frequency of the higher note will be: $$f_2 = 2f_1 = 2(100\text{ Hz}) = 200\text{ Hz}$$

The octave relationship is an important one in music, as it forms the basis for many musical scales and harmonies.