Question

find a formula for the a sub n term

Answer 1

{8,0,8,0...}

Answer 2

\[a _{n}\]

Answer 3

\[a_n =-4(-1+1^n))\]

Answer 4

Wait, that should be a -1, (-1)^n

Answer 5

so -4(-1-1)^n ?

Answer 6

\[a_n=-4(-1+(-1)^n)\]

Answer 7

ooohh.. I can see this now... wow this one is odd

Answer 8

Idk how i would have figured this out...

Answer 9

can someone show me how i could have figured that out by myself? like arithmetic or a rule or something

Answer 10

Start like this:
\(a_n = (-1)^n\) to get
-1, 1, -1, 1, -1, ...

Then multiply the sequence by 4 to get:
\(a_n = 4(-1)^n \)
-4, 4, -4, 4, ...

Change the 4 to -4 to get:
\(a_n = -4(-1)^n \)
4, -4, 4, -4, ...

Now add 4 to get:
\(a_n = -4(-1)^n + 4 \)
8, 0, 8, 0, ...

Now factor out 4 and rearrange to get:
\(a_n = 4[1 - (-1)^n]\)