Question

What is the explicit formula for the sequence below? 4, -12, 36, -108 ...

Answer 1

Answer:x ×-3

Step-by-step 4×-3= -12

-12 × -3= 36

and so on

Answer 2

Answer:
an = -6*(1/4)^(n-1)
Step-by-step explanation:
We have that the recursive formula for the given geometric sequence is:
a1 = -6
an = (an-1) * (1/4)
With the above we can assume that:
r = 1/4
following the rule of the explicit formula that is given by:
an = a1 * (r) ^ (n-1)
we substitute and we have:
an = -6 * (1/4) ^ (n-1)
Therefore the explicit formula from the given data would be:
an = -6 * (1/4) ^ (n-1)