Opening the vowels/Mixed Voice

 Hi ! 

We spoke 2 days ago.

I came back with some feedback ! 

• You told me to use the  AY legatto as the word "day" to  hit above D4#, i  tried that  and it is alright but its much easier with the vowel A like the latins therms.
• When i go above  D4# to hit that E4 AND F4 sometimes F4#, i'm droping my  jaw more and opening  a little bit more the  throat.
• IS THAT ALRIGHT ? I MEAN, ITS A BIT SHAKY but not shouty, it feels  kind of good and the chromatic tunner tells me  that's the note. 
• By the way, i use your exercices for pitch and intonation,  for the moment its get better sometimes a bit flat between the notes, like i want to sing a D4# and its a little bit shaky(between D4-D4#) but  its  not so flat.
• It is almost a D4# but  not  perfect. 
• The same with the rest above D4#
• CAN I GET ANOTHER ADVICE  TO  DISCOVER MY MIXED VOICE  OR SHOULD I CONTINUE WTH THE "A" IN SCALES LIKE:
• G MAJOR G B D ? 

Yes, A as in CAT is another good vowel shape if the "flat and wide" approach works for you. In general, I find that male singers do better with the AY or A shape, and female singers do better with the "tall and narrow" approach - but you can certainly try singing on NOH or BUHB (with the jaw relaxing down). 

If it feels shaky but good, and not shouty, then it sounds like you're on the right track!

You can use any melodic pattern you like - this video will have some more ideas for you: https://www.youtube.com/watch?v=0soCFM4YSIE

I GOT THIS , BUT I CAN'T SUSTAIN VERY MUCH ..

I CAN HIT  ALMOST A G4 with  the NO but i can't sustain above D4# VERY WELL..

That's alright! Work on sustaining gradually. For now, you can fall off the "no"; then, try holding the high note before falling off; then, sustain for longer without falling off.