Determine if the following is an arithmetic, geometric, or neither. 6. 6,9,14,21,30 7. 1,-3,5,-7 8. 80,40,20,10 9. 20,30,36,42 10.100,-50,25,-12.5

Question

Determine if the following is an arithmetic, geometric, or neither.

6. 6,9,14,21,30

Answer 1

6) The terms differ by an increasing amount: 3, 5, 7, 9. So this is not an AP or a GP, but a quadratic progression. An AP would have a constant common difference and a GP a constant common ratio. Ans: neither.

7) Neither

8) Geometric, because of constant ratio ½.

9) Neither

10) Geometric, constant ratio -½.