Question

Tell whether each sequence is arithmetic. Justify your answer. If the sequence is arithmetic, write a recursive formula and an explicit formula to represent it.
1. 0.3, 0.9, 1.5, 2.1

2. 1, 8, 27, 64

Answer 1

Step-by-step explanation:

an arithmetic sequence is when every new term is created by adding a certain constant to the previous term.

1. is an arithmetic sequence. the constant is 0.6.

0.3 + 0.6 = 0.9

0.9 + 0.6 = 1.5

1.5 + 0.6 = 2.1

...

so, we have

a1 = 0.3

an = an-1 + 0.6

and

an = a1 + (n-1)×0.6 = 0.3 + (n-1)×0.6

2. is neither an arithmetic nor a geometric sequence.

it is simply

an = n³