[填空题]
An unfingered guitar string in +svkw42b fto6sk9/ bac-r 1as 0.73 mmtun9v2i7- qqg-5mvf z w+s5 yk+9otv long and is tuned to play E above middle C (330 Hz).m 5syk2m 7v5vi+gqtvno 9 zwt-fu+9q- (a) How far from the end of this string must the finger be placed to play A above middle C (440 Hz)?$\approx$ m
(b) What is the wavelength on the string of this 440-Hz wave? $\approx$ m
(c) What are the frequency and wavelength of the sound wave produced in air at 20°C by this fingered string? Hz m