Question

What is the value of a1 of the geometric series? Sigma-Summation Underscript n = 1 Overscript infinity EndScripts 12 (negative one-ninth) Superscript n minus 1 Negative twelve-ninths Negative one-ninths 1 12

Answer 1

Answer:

12

Step-by-step explanation:

The given geometric series is

$\sum_{n = 1}^{ \infty} 12( { - \frac{1}{9} })^{n - 1}$

We want to determine the first term of this geometric series.

Recall that the explicit formula is

$a_{n} = 12( { - \frac{1}{9} })^{n - 1}$

To find the first term, we put n=1 to get:

$a_{1} = 12( { - \frac{1}{9} })^{1 - 1}$

This gives us:

$a_{1} = 12( { - \frac{1}{9} })^{0}$

$a_{1} = 12(1) = 12$

Therefore the first term is 12

Answer 2

Answer:

12

Step-by-step explanation:

The last option, C is the answer. I just took the quiz :D