Altered Major Chord

Hi,

A common alteration on the major chord is to add a #11.

The formula of a Cmaj7#11 is 1 3 5 7 #11

#11 is to raise the 4th degree by half step.

4th in C is a F. Raise half a step is F#.

So the chord tone in a Cmaj7#11 is C E G B F#.

You can easily improvise over the Cmaj7#11 with the C major Pentatonic or Lydian scale.

Have Fun!