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
