Let Tr be the rth term of an A.P. whose first term is a and common difference is d. If for some positive integers m,n, m≠n,Tm=1n and Tn=1m, then a-d
0
1m+1n
1mn
1
Tm=a+m−1d=1n, Tn=a+n−1d=1m
Solving a=1mn and d=1mn ⇒a−d=0