Question

What is n^th term of an A.P.?

(a) an = a + (n-1) d

(b) an = a + (n) d

(c) an = a*r^n-1

(d) an = a*r^n

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

My doubt is from Arithmetic Progression(A.P.) in division Sequences and Series of Mathematics – Class 11

Answer 1

The correct choice is (a) an = a + (n-1) d

To explain I would say: Since every term of an A.P. is incremented by common difference d.

i.e. an+1 = an + d = an-1 + 2d = ……. = a1 + n*d

or an = a + (n-1) d