Using special techniques called string harmonics (or "flageolet tones"), stringed instruments can produce the first few overtones of the harmonic series. While a violinist is playing some of these harmonics for us, we take a picture of the vibrating string (see figures). Using an oscilloscope, we find the violinist plays a note with frequency f = 805 Hz in figure (a). Part How many nodes does the standing wave in figure (a) have?