Question

if in an ap mth term is n and nth term is m show rth termis m+n-r

Answer 1

nth term = m
》a+(n-1)d = m.........(equ1)

mth term = n
》a+(n-1)d = n..........(equ2)

Solve equ2 and equ1 for d,
you will get d = -1. Put this in either equ2 or equ1. You will get a = m+n-1

Now rth term = a+(r-1)d
= m+n-1+(r-1)×(-1)
= m+n-r