Violinists sometimes bow a string to produce maximum vibration (antinodes) at one-quarter and three-quarters of the string

Question:

Violinists sometimes bow a string to produce maximum vibration (antinodes) at one-quarter and three-quarters of the string length rather than at the middle of the string. Then the string vibrates with a wavelength equal to the string length rather than twice the string length. (See Figure 19.13 a. and b.) What is the effect on the frequency when this occurs?

Figure 19.13

(a)