Question

Is the sequence 7, 9, 11, 13,.. A)arithmetic B)geometric C) both D)netheir

Answer 1

This sequence is arithmetic, because each number is the last number plus two.

Answer 2

The correct option will be: A) Arithmetic

Explanation

If a, b, c,.... is a sequence, then

It will be arithmetic sequence when $2b = a+c$

and it will be geometric when $b^2 = a*c$

The given sequence is 7, 9, 11, 13, ....

Here, a= 7, b= 9, c= 11

Arithmetic check

$2b= a+c \\ \\ 2(9)= 7+11\\ \\ 18=18 (True)$

Geometry check

$b^2= a*c\\ \\ 9^2 = 7*11\\ \\ 81 = 77 (False)$

So, we can see that the given sequence satisfies the arithmetic rule. That means it's Arithmetic sequence.