Question

Find an explicit rule for the nth term of the sequence.

3, -12, 48, -192, ...

Answer 1

@johnweldon1993

Answer 2

\(\large\color{black}{ Common~~ratio=a_{n}\div a_{n-1}=a_2 \div a_1=(-12)\div 3=-4\LARGE\color{white}{ \rm │ }}\)

Answer 3

an = a1(r)^(n-1)

just plug in the numbers and you get an = 3(-4)^(n-1)

Answer 4

You weren't right, but close, your common ratio is not 4, but `-4`.

Answer 5

And it is to the power of `n-1`, not to the power of `n+1`.

Answer 6

got it (: @SolomonZelman

Answer 7

Yes, that would be correct.

Answer 8

Good work :)

Answer 9

youre the best!!

Answer 10

Not really, but tnx :)