Final answer:
The note D Sharp/E Flat (above staff) is the same musical note that can be represented either as a D raised by a semitone or an E lowered by a semitone. In musical notation, the mnemonic 'Every good boy does fine' helps remember the lines of the treble clef. Beat frequencies occur when notes like F, F-sharp, and G are played together on a piano.
Step-by-step explanation:
The note represented by D Sharp/E Flat (above staff) is a musical note that lies above the five lines of the musical staff in the treble clef. The mnemonic 'Every good boy does fine' helps beginners remember the notes E, G, B, D, and F on the lines of the treble clef, with D being the second to top line.
However, when you see a D Sharp or E Flat, the note is a semitone higher than D or a semitone lower than E respectively, depending on whether it is described as sharp or flat. This note can also be found on string instruments, where the standard notes of the six strings are tuned to specific frequencies with the low E being the lowest frequency and the high E the highest of the six.
In the context of playing multiple notes on a piano, for instance, striking the keys for F, F-sharp, and G simultaneously would create a discordant sound with specific beat frequencies resulting from the different frequencies of the notes played.
Beat frequencies are created when two or more notes of different frequencies are played together. When we have three keys such as F, F-sharp, and G played at the same time, the resultant beat frequencies would be the absolute difference between the frequencies of the notes, with the pairs producing 21 Hz (370 Hz - 349 Hz) and 22 Hz (392 Hz - 370 Hz) respectively.
These frequencies illustrate the interference of waves and how the sound is perceived as a beating effect due to the variance in the frequencies struck.