A Progression is said to be Harmonic Progression or \(H.P.\) if the reciprocals of its terms, are in Arithmetic Progression.

In other words \({t_1},{t_2},{t_3}\),……. are in H.P. if \(\frac{1}{{{t_1}}},\frac{1}{{{t_2}}},\frac{1}{{{t_3}}},\,\,\,.........\,\) are in A.P. Thus, we have 

\(\frac{1}{{{t_n}}} = \frac{1}{{{t_1}}}\,\, + \,\,(n - 1)d\)

To calculate \({n^{th}}\) term of a \(HP\), we can first calculate \({n^{th}}\) term of the AP obtained by taking reciprocals of the corresponding terms of  the given \(HP\). Now taking reciprocal of this \({n^{th}}\) term we get the required term of \(HP\). 

Note that all the terms of an \(H.P.\) must be non-  zero.