Question

Find the first five terms of the geometric sequence for which a1= 3 and r=-2?

Answer 1

\[a_{n} = a_{1}*r^{n-1}\]

Answer 2

i dont know how to find n

Answer 3

n is the number of the term you're finding.

Answer 4

oh!

Answer 5

You already know that a1 = 3, so the next one you want is a2 where n = 2.

Answer 6

So as an example,
\[a_2 = 3 * -2^{2-1} = -6\] And this just needs to be repeated until you get to 5.

Answer 7

is \[a _{3}=12?\]

Answer 8

Yes.

Answer 9

so 3, 6, 12, 24, 48?

Answer 10

Don't forget about the negative sign on r.

Answer 11

did i do it wrong?

Answer 12

It should be 3, -6, 12, -24, 48 because r=-2, not just 2.

Answer 13

oh!

Answer 14

thanks i have more questions still haha..

Answer 15

Start a new question for any separate questions.