Question

Determine whether the sequence is geometric or arithmetic. Then give the general formula for the nth term of the sequence.

6.1, 6.9, 7.7, 8.5, 9.3,...

I think it is Geometric, but i don't know how to find the formula

Answer 1

If it's geometric, the ratio of successive terms does not change:

6.9/6.1 = 1.131
7.7/6.9 = 1.116
...
not geometric

If it's arithmetic, the difference between terms does not change:

6.9-6.1 = .8
7.7-6.9 = .8
8.5-7.7 = .8
9.3-8.5 = .8
looks like an A.S. to me.

Answer 2

Determine the 8th term of the following arithmetic sequence. -7, 2, 11, 20...