sequences

[djw127]

I have a question that I feel like it is pretty easy but for some reason my brain won't allow me to solve it.
Consider the following sequence:
8,-8,8,-8,8,.....


Write a formula for the nth term of this sequence:
an=

I would appreciate anyone who can help. thanks

 

[iambryanatkinson]

for alternate positive/negative value of sequences, function (-1)[sup:ry2y6lby]n[/sup:ry2y6lby] is very useful

the function gives value of -1,1,-1,1,...

to start the sequence with positive value just use (-1)[sup:ry2y6lby]n+1[/sup:ry2y6lby] which gives 1,-1,1,-1,...

using this, your answer is
an=8*(-1)[sup:ry2y6lby]n+1[/sup:ry2y6lby]

 

[djw127]

Oh wow that was a lot more simple than I was making it. Thanks for the help!!