Astring of length l is rigidly held at both ends. the string is plucked—like you might strum a guitar string—and a standing wave is formed in the string. the fundamental frequency for this standing wave is f sub 1 is equal to start fraction 1 over 2 times l end fraction times start square root of start fraction t over mu end fraction end square root, where t is the tension in the string and mu is the mass density of the string. what is the frequency of the third harmonic, or second overtone?