def tet_f(note, tuning=440):
    """Returns the frequency of a note given in scientific notation."""

    # parse note as nth semitone from A0
    letter = note[:-1]
    octave = int(note[-1])
    note_names = ["C", "C#", "D", "D#", "E",
                  "F", "F#", "G", "G#", "A", "A#", "B"]

    letter_index = note_names.index(letter) + 1
    note_number = octave * 12 + letter_index - 9

    # apply formula
    return tuning * ((2 ** (1 / 12)) ** (note_number - 49))