Question

Which explicit formula describes the sequence

use the picture for the full question​

Answer 1

• First term=a=1
• Common ratio=4/49÷2/7=4/49×7/2=2/7

Now the explicit formula

• ar^{n-1}
• 1(2/7)^{n-1}
• (2/7)^{n-1}

Option A

Answer 2

• A. aₙ = (2/7)ⁿ⁻¹

Explanation:

According to sequence we observe:

• the first term is a₁ = 1
• the common ratio is r = 2/7

Equation of nth term of GP:

• aₙ = a₁r°⁻¹

Substitute to get:

• aₙ = 1*(2/7)ⁿ⁻¹ = (2/7)ⁿ⁻¹

Correct choice is A