Question

What is the recursive formula for this geometric sequence?–3, –21, –147, –1029, ..?

Answer 1

This is geometric sequence,
$a_{1}= -3, r= \frac{-21}{-3} =7 a_{1}=-3, a_{n}=7*a_{n-1}$
Last line made of 2 equation is a recursive formula.

Answer 2

The recursive formula for this geometric sequence will be given as $\rm a_n = -3 \cdot \left ( \dfrac{1}{7} \right)^{n-1}$.

What is the geometric sequences?

Let a₁ be the first term and r be the common ratio. Then the geometric sequences will be

$\rm a_n = a_1 \cdot r^{n-1}$

The geometric sequence is given as,

–3, –21, –147, –1029, ..

The first term will be -3.

And the common ratio will be

⇒ (-3)/(-21)

⇒ 1/7

Then the recursive formula for this geometric sequence will be

$\rm a_n = -3 \cdot \left ( \dfrac{1}{7} \right)^{n-1}$

More about the geometric sequences link is given below.

https://brainly.com/question/11266123

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