Sequences

[Probability]

Could somebody who understands sequnces please advise me with regards the following.

If I have terms; 4, 7, 10, 13 ...

the common difference is 3

But if I had - 2.8, - 1.6, - 0.4, 0.8

How can I find the common difference there as I don't think there is one?

I have been reading maths books but all their examples are all based on my set of terms above.

Please advise if you can.

 

[pka]

Could somebody who understands sequnces please advise me with regards the following.
But if I had - 2.8, - 1.6, - 0.4, 0.8
How can I find the common difference there as I don't think there is one?

\(\displaystyle (-1.6)-(-2.8)=1.2\)
\(\displaystyle (-0.4)-(-1.6)=1.2\)
\(\displaystyle (0.8)-(-0.4)=1.2\)

 

[Probability]

\(\displaystyle (-1.6)-(-2.8)=1.2\)
\(\displaystyle (-0.4)-(-1.6)=1.2\)
\(\displaystyle (0.8)-(-0.4)=1.2\)

Thank you, I originally started with 1.2, I feel really thick now