anonymous one year ago Is this arithmetic or geometric ? $${4n^2}$$ Not sure how to approach this one. Do I $$4(n-1)^2$$

1. anonymous

This has to do with Sequences

2. anonymous

@peachpi

3. anonymous

it's neither

4. anonymous

How do I check? Do I just 4*1^2 =16 4*2^2 = 64 and then check the for the difference and ratio ?

5. anonymous

you can do 3 consecutive terms to check. $a_1=4(1)^2=4$ $a_2=4(2)^2=16$ $a_3=4(3)^2=36$ If $$\frac{ a_2 }{ a_1 }=\frac{ a_3 }{ a_2 }$$ then it's geometric. If $$a_3-a_2=a_2-a_1$$, then it's arithmetic

6. anonymous

Neither of those is true so the sequence is neither arithmetic or geometric

7. anonymous

Ok, that is what I was thinking. Thank you and I messed up on my on my powers. I was thinking (4*1)^2 for some reason but it is the way you have it.

8. anonymous

no problem. the geometric sequences will look like exponential functions and arithmetic sequences look like linear functions. If it's a higher order polynomial or some other type of function it's neither.