High School Pre-Cal

Question

What is the 14th term of the sequence below?

2, 6, 18, 54, . . .


A.1,594,323

 

B.3,188,646

 

C.4,782,969

 

D.9,565,938

Answer 1

Hi Kenneth,

 

the formula for the nth term of a geometric series is

 

an = a1r^n-1

 

where the first term is 2 and r is 3 (each term is increased by a factor of 3)

 

you can always find r by choosing a term and dividing by the term before it

 

a₁₄ = 2·3¹³

 

= 3,188,646

 

answer B