b flat
There is not three notes in any scale or key, if you are asking about the accidentals, there is one flat (Bb) in the key signature plus an additional C sharp for the harmonic minor scale.
The relative major key of B minor is D major. It has a key signature of F# and C# and a raised 7th of A#.
D major has a key signature of F sharp and C sharp D minor has a key signature of B flat
This is called the Key Signature.
YOU learn about accidentals in level 2 in piano. Accidentals in piano are when there are flats or sharps next to a note that was not given in the key signature.
b flat
Johann Sebastian Bach 'discovered' the chromatic scale, and composed the Circle of Fifths. The Circle of Fifths starts with the key of C, which has no accidentals (flats or sharps). The fifth note of C is G, when means when you play or write these scales, you move from the key of C to the key of G - moving up a perfect fifth; hence, the term 'circle of fifths'. The key of G major has one accidental, the F sharp. The fifth note of the key of G is D, and the key of D major has TWO sharps - so you see, as you move through the circle of fifths each change increases the number of accidentals by one. For instance, the fifth note of D is A, and the key of A major has THREE accidentals. That is pretty much why the key of G major has an accidental, which in the case of that scale, happens to be F sharp.
A natural sign cancels all applicable accidentals in that bar as well as accidentals in the key signature. However, in the case of the key signature accidentals, the natural sign is only applicable to that bar.
Instead of writing a sharp in the key signature, write one next to the F when you write out the scale.
The key signature of the D major key has nine sharps: F, C, G, D, A, E, B, and F.
The tonic in D major is D.
In the key of D major, the notes that are sharp are F, C, and G.
There is not three notes in any scale or key, if you are asking about the accidentals, there is one flat (Bb) in the key signature plus an additional C sharp for the harmonic minor scale.
D major has F# and C# in it's key signature.
look for any accidenatls in the scale. If there are no accidentals, then it's a major scale, vise versa. All the sharps and flats should be included in the key signature of the scale.
The white notes E -> F and B -> C are a semitone apart. They do not require accidentals when present in any key in which those particular notes are not altered in the key signature, but do require accidentals if the corresponding notes in the key signature automatically raise or lower them by a semitone accordingly.