205k views
2 votes
Use your formula from question 2c to find the values of t7 and t20. (r=7; 2,14,98,686) (Geometric Sequence)​

User Slashdot
by
3.8k points

1 Answer

5 votes

Answer:

Correct answer: t₇ - a₇ = 2 · 7⁶, t₂₀ - a₂₀ = 2 · 7¹⁹

Explanation:

Given:

Geometric sequence 2, 14, 98, 686, ......

First term is a₁ = 2

Second term a₂ = 14

Third term a₃ = 98

The quotient ( ratio) is obtained as follows:

r = 14 / 2 = 98 / 14 = 7

r = 7

n-th term is obtained as follows:

aₙ = a₁ · rⁿ⁻¹

according to this:

a₇ = 2 · 7⁶ = 2 · 117,649 = 235,298

a₂₀ = 2 · 7¹⁹ = 2 · 11,398,895,185,373,143 = 22,797,790,370,746,286

God is with you!!!

User Tkocmathla
by
4.4k points