Question

What are the first four terms of the geometric sequence an=2 an-1 and a1=3​

Answer 1

Answer:

B.$3,6,12,24$

Step-by-step explanation:

We are given that

$a_n=2a_{n-1}$

$a_1=3$

We have to find the first four terms of G.P

Substitute n=2

$a_2=2a_1=2(3)=6$

Substitute n=3

$a_3=2a_2=2(6)=12$

Substitute n=4

$a_4=2a_3=2(12)=24$

Hence, the first four terms of G.P are  given by

$3,6,12,24$

Option B is true.

Answer 2

Answer:

3, 6, 12, 24

Step-by-step explanation:

This is a recursive formula which allows the next term in a sequence to be found from the previous term in the sequence

Given

$a_{n}$ = 2$a_{n-1}$ with a₁ = 3, then

a₂ = 2 × a₁ = 2 × 3 = 6

a₃ = 2 × a₂ = 2 × 6 = 12

a₄ = 2 × a₃ = 2 × 12 = 24

Thus the first 4 terms are 3, 6, 12, 24