Question

is this series geometric -1,1,4,8

Answer 1

hmm, a series is a sum of the terms of a sequence, not the sequence itself ....

what is your definition of a geometric sequence?

Answer 2

A common ratio to describe how to get from on to the next

Answer 3

then lets see if we can find a common ratio

-1 * r = 1
1 * r = 4
4 * r = 8

hmm, does this look doable to you?

Answer 4

Not too sure I understand

Answer 5

well in order to get from the first term of 1 to the second term of -1, the for some value of r, we just multiply it out

same idea for 2nd to 3rd, and 3rd to 4th

Answer 6

if we solve each instance for r, and find that it is the same each time, then there is a common r (for ratio) that gets us from one term to the next

Answer 7

It looks like a consecutive integer problem in a way

Answer 8

almost :) but lets solve each instance for r to see if it remains the same

-1 * r = 1
r = -1


1 * r = 4
r = 4


4 * r = 8
r = 2

since r is changing, the ratio between terms is not constant .... so this cant be geometric

Answer 9

Ok thank you so much

Answer 10

yep