Question

I would like my answer to this one checked as well. Would it be considered geometric sequence even if the common ratio is slightly different for each one? They are each a few decimals apart.

The instructions are the same as in my previous question:


Determine if the sequence is arithmetic , geometric, or neither.

Answer 1

Neither arithmetic nor geometric

Explanation:

Why not Geometric?

Find common ratio

`\\ \sf\longmapsto (-9)/(10)=-0.9`

`\\ \sf\longmapsto (8)/(-9)=-0.89`

• If you round up 2nd one then it also becomes -0.9.

But the ratios are not same so it's not geometric.

Verified.

Why not Arithmetic?

Find common difference

`\\ \sf\longmapsto -9-10=-19`

`\\ \sf\longmapsto 8-(-9)=8+9=17`

• .Here common differences are not same .
• So it's not an arithmetic progression.

Verified.

Answer 2

Neither.

Explanation:

10, -9, 8, -7, 6. -5 4.

-9/10 = -0.9

8/-9 = -0.89

-7/8 = -0.875

The ratios are close but different so it is not geometric.

Neither is it arithmetic because the differences in the terms are not common.