Question

an = 4(−5)n − 1

an = 4(one fifth)n − 1

an = 0.4(5)n − 1

an = one fifth(4)n − 1

Answer 1

What happens to the y value when going from
4 to 0.8 ?
0.8 to 0.16 ?

Answer 2

multiplied by .2?

Answer 3

yes, exactly !

Answer 4

And 0.2 = 1/5
So, your common ratio is 1/5
And you know that the first term, a1, is 4.

Answer 5

ooohhh wow i didnt even think of that lol

Answer 6

ok so that eliminates A and C

Answer 7

with that being said it should be D right?

Answer 8

if you say D, then it would mean that the ratio is 4, and the first term is 1/5

BUT it is the other way around.

Answer 9

oh so your first term is always in front of your ratio?

Answer 10

yes, because the ratio goes to the power of `n-1` for any `n`th term, right ?

Answer 11

\(\large\color{blue}{ a_n=a_1\times r^{n-1}\LARGE\color{white}{ \rm │ }}\)

Answer 12

it is always like this:)

Answer 13

ok great tank you!

Answer 14

Which option do you pick? (Just to make sure)

Answer 15

B

Answer 16

Yeah...\(\large\color{blue}{ a_n=5\times(⅕)^{n-1}\LARGE\color{white}{ \rm │ }}\)