Question

What is the recursive formula for the sequence 12, 7, 2, -3, ...? a. a1=12,an=-5 b.a1=12,an=an-1-5 c.a1==12,an=an-1+5 d.a1=12,an=an+1+5

Answer 1

For this case we have the following sequence:

12, 7, 2, -3,....

We can find the common difference on this way:

d= 7-12= -5

And then the can create the formula on this way:

a1 = 12

an = an-1 -5

Then the best answer would be:

b.a1=12,an=an-1-5