Question

The 6th term of a gp is -2/29,and it's first term is 18.what is the common ratio​

Answer 1

Answer:

-0.329

Step-by-step explanation:

The formula for Geometric ratio is

an = ar^n - 1

Where

a = First term = 18

r = Common ratio = ?

n = Number of term= 6

Hence

a6 = 18 × r^6-1

From the question

a6 = -2/29

Hence:

-2/29 = 18 × r^6-1

-2/29 = 18 × r⁵

Divide both sides by 18

-2/29 ÷ 18 = 18 × r⁵/18

-2/29 × 1/18 = r⁵

r⁵ = -1/261

Take the fifth root of both sides

⁵√(r⁵) = ⁵√(-1/261)

r = -0.3286032834

Approximately = -0.329

Therefore, Common ratio = -0.329