In my old theory book, I read that while ii and ii6 harmonize scale degrees 2 and 4, they rarely harmonize scale degree 6 in the soprano. (I'm assuming they mean for common practice music, SATB). ...
If I know that this triad is in the key of A major, how can I tell if this a root, first inversion, or second inversion? I know in second inversion, the fifth is usually doubled, but how can I tell ...