what is the harmonic theorem

Question

anonymous · Answer

sorry i found out that it was harmonic progression i was looking for

anonymous · Answer

In mathematics, a harmonic progression is a progression formed by taking the reciprocals of an arithmetic progression. In other words, it is a sequence of the form
           a                 a                 a
a, -------- , -------- , --------
       1 + d          1 + 2d      1 + 3d

anonymous · Answer

12                  12
12, 6, 4, 3, ---- , 2, … , -----
                      5                    n

anonymous · Answer

Harmonic Mean 

                 2ac
b  =   -------------
              a + c