Question

(40 points)

What is the recursive rule for the sequence?

−7.4, −21.2, −35, −48.8, −62.6, ...




an=an−1−13.8 , where a1=−7.4

an=an+1+13.8 , where a1=−7.4

an=an+1−13.8 , where a1=−7.4

an=an−1+13.8 , where a1=−7.4

Answer 1

a1 = -7.4

an = an-1 - 13.8

Explanation:

To find the common difference take the second term and subtract the first term

-21.2 - (-7.4) = -13.8

Check by taking the third term and subtracting the second term

-35 - (-21.2) = -13.8

The common difference is -13.8

The first term is -7.4

Recursive rule

Means finding the next term in terms of the previous

a1 = -7.4

an = an-1 - 13.8