D-flat major. It's the enharmonic equivalent.
The dominant (fifth) degree of a D sharp major scale is A sharp.
E to F-sharp is one whole step. F-sharp is a major 3rd above D, so it's part of the D major scale.
No scale has an F♯ and a D♯ alone, however the keys of E, B, F♯, C♯ major and likewise their relative minors have both the notes F♯ and D♯ as degrees in their scale.
D major isn't actually a note. D major is a major scale based on the note D (D natural) and the scale has two sharps (F sharp and C sharp). There isn't anything special about D major since it requires both an F sharp and a C sharp, the most 'special' scale is C major since there are no flats or sharps needed.
The scale of 'C' - it uses neither sharp or flat notes.
The mediant of any major scale is the note that is a third above the tonic (root) of the scale. In the key of F sharp major, the tonic is F sharp, so the mediant would be A sharp.
G major, D major, E major, B major, F sharp major, F sharp minor, A sharp major, etc.
The G-major scale has only one sharp (which is F#)
The subdominate refers to the fourth note of the scale ( assuming it is a diatonic scale). In this case the subdominate of the C sharp major scale would be F#.
G Major has one sharp, which is F sharp.
C, F, and G are sharp in this scale.
The dominant (fifth) degree of a D sharp major scale is A sharp.
That would be C-sharp major. Every note is sharp.
Technically speaking, D sharp major is: D#, E#, F* (F double Sharp,) G#, A#, B#, C* (C double sharp) D#. ***note: a double sharp (*) means that the note sounds a whole step above the principal note. For example: F*=G.
The major scale with 2 sharps is D major, they are F and C sharp.
C# major, E major, A major, B major, and C# minor.
The D Major scale has two sharps, F and C. The notes in this scale are D, E F sharp, G, A, B, C sharp, D.