Prove that no matter what the real numbers a and b are, the sequence with nth term a+nb is always an A.P. What is the common difference?
Given sequence with n th term defined by tn= a + nb
So tn-1= a + (n-1)b
⇒ tn - tn-1 = a + nb - a - b(n-1)
⇒ tn - tn-1 = b
Therefore, the difference between the preceding term and next term of this sequence is independent of 'n '.
Hence this sequence is an AP with common difference b.