# If there be 'm' A.P's beginning with unity whose common difference is 1,2,3......m. Show that the sum of their #n^(th)# terms is #(m/2)(mn-m+n+1)#?

##### 1 Answer

Aug 28, 2017

The first AP series

The 2nd AP series

The 3rd AP series

The

So sum of nth terms of m AP series will be

**Another approach**

Here the number of terms for all nth terms of m AP series is

First term of the series

The common difference of the series

So applying formula