Mathematics

Problem

In an arithmetic progression, the

m

th term is

n

and the

n

th term is

m

, where

m

and

n

are distinct positive integers. a. (i) Show that the common difference of the progression is

-1

. b. (ii) Find the first term in terms of

m

and

n

. c. (iii) Hence obtain the sum of the first

(m+n)

terms.