Please help describe the sequence as arithmetic geometric or neither. For arithmetic and geometric sequences give the common difference or common ratio.

Question

1. {3,-6,12,-24,-48...}

2.{-11/4,-2,-5/4,-1/2,1/4...}

3.{3600,1440,576,230.4,...}

4.{600,-300,100,-25...}

Answer 1

#1. check for common difference
-6-3 = -9; 12-(-6) = 18 ≠ -9 so not arithmetic
check for common ratio
-6/3 = -2; 12/-6 = -2 so the common ratio is -2; geometric
(assuming the ratio holds for the rest of the terms)

Now you try the others.