Question:

If n1, n2, and n3 are the fundamental frequencies of three segments into which a string is divided, then the original fundamental frequency n of the string is given by:

1√n=1√n1+1√n2+1√n3

n=n1+n2+n3

1/n=1/n1+1/n2+1/n3

√n=√n1+√n2+√n3

n1=1/(2l1)√(T/μ)
n2=1/(2l2)√(T/μ)
n3=1/(2l3)√(T/μ)
n=1/(2l)√(T/μ)
l=l1+l2+l3
1/n=1/n1+1/n2+1/n3