This is a major scale.
1, 2, 3, 4, 5, 6, 7, 8.
2nd, 3rd, 4th, 5th, 6th, 7th, 8th. Octave.
Major 2nd, Major 3rd, Perfect 4th, Perfect 5th, Major 6th, Major 7th. Octave.
Major 2nd, minor 2nd...Major 3rd, minor 3rd...Perfect 4th, Perfect 5th...Major 6th, minor 6th...Major 7th, minor 7th. Octave.
An inversion happens when you take the bottom note of an interval and play it an octave higher.
This is a minor 7th. It is the same interval as this.
So a Major 2nd inverts to a minor 7th.
A Major 3rd inverts to a minor 6th.
A Perfect 4th inverts to a Perfect 5th.
And a Perfect 5th inverts to a Perfect 4th.
These intervals invert to one another.
If this was a Major 4th, and this was a Major 5th, then a Major 4th would invert to a Major 5th, and a Major 5th would invert to a Major 4th.
You would have Major intervals inverting to other Major intervals.
Perfect 4th...Perfect 5th.
Major 2nd, Major 3rd, Perfect 4th, Perfect 5th, Major 6th, Major 7th. Octave.
Notice that I didn't talk about that interval---
The "Devil's" interval.
