Question

Which of the following sequeces in AP will have common difference 3, where n is an Integer?

(a) an = 2n^2 + 3n

(b) an = 2n^2 + 3

(c) an = 3n^2 + 3n

(d) an = 5 + 3n

I had been asked this question by my college professor while I was bunking the class.

Asked question is from Arithmetic Sequences in section Basic Structures: Sets, Functions, Sequences, Sums and Matrices of Discrete Mathematics

Answer 1

Right answer is (d) an = 5 + 3n

To elaborate: an = 5 + 3n it is a linear expression with coefficient of as 3. So it is AP with common difference 3.