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

4, -4, 4, -4, ...

Question

Find an explicit rule for the nth term of the sequence.

4, -4, 4, -4, ...

anonymous · Answer

@andrewhaze @mathstudent55 @bohotness @undeadknight26

anonymous · Answer

@campbell_st @Nnesha

freckles · Answer

it is alternating in sign only
hint: think about (-1) as the common ratio.

bohotness · Answer

what is the question

anonymous · Answer

find the explicit rule @bohotness

campbell_st · Answer

well what is each term being multiplied by..?

campbell_st · Answer

1st term is 4

anonymous · Answer

I know that

anonymous · Answer

My answer choices are:
1.an=4*1^n-1
2.an=4*1^n+1
3.an=4*(-1)^n
4. an=4*(-1)^n-1

anonymous · Answer

@campbell_st

anonymous · Answer

@bohotness

anonymous · Answer

@skate-4-life270

nnesha · Answer

oky so do you know explicit formula ??

anonymous · Answer

its positive then negative negative but the difference between the two is 8

anonymous · Answer

@skate-4-life270 its actually positive negative positive negative....

nnesha · Answer

is it geometric or arithmetic ???

nnesha · Answer

do you know ^^^this ??

anonymous · Answer

IDK....honestly
@Nnesha

nnesha · Answer

okay when number increasing by multiplying or dividing some number then  geometric
and if you are adding or subtracting previous term to get next one then its arithmetic 
first terms is 4
2nd one is -4
what you should with 4 to get "negative" 4??

anonymous · Answer

multiply by -1 @Nnesha

nnesha · Answer

yes right so then its geometric or arithmetic ??

anonymous · Answer

geometric @Nnesha

nnesha · Answer

yes right

nnesha · Answer

so explicit formula for geometric is $$a _{n} =a _{1} \times r ^{n-1}$$

anonymous · Answer

The answer is  4 x -1^n so answer 3.

nnesha · Answer

r is ratio 
a1 is first term

nnesha · Answer

welcome to open study @itsreallykalen http://openstudy.com/code-of-conduct <--- this is for you

anonymous · Answer

so which one would it be 3 or 4?? @Nnesha @itsreallykalen Because y'all are giving me two different answers

nnesha · Answer

ratios is -1
a1 terms is 4
now replace a1 and r by their values and see which one is ur answer

anonymous · Answer

so it would be answer 3?? @Nnesha

nnesha · Answer

you mean answer choices= 3

anonymous · Answer

yes sorry...

nnesha · Answer

nvm

nnesha · Answer

oaky nope its not 3 sorry :(

anonymous · Answer

So then it would be 4??

nnesha · Answer

|dw:1421789697642:dw|
i gave you the formula