A taut string of 1.00 meters in length is fixed at both ends. You place your finger on the midpoint of the string (exactly halfway between the two fixed ends), thus forcing a node in the middle of the string. You then pluck the string lightly. If the speed of waves on the string is 23.8 m/s, what is the lowest frequency of vibration of the string that will be produced? Enter an answer in Hertz (seconds^-1).