the answer is D u are welcome
D. a_n = 9 − 6(n − 1) where n ≥ 1
If a_n = 4(3)^n−1 , what is S_3?
Select one:
a. 12
b. 36
c. 16
d. 52
2 answers
The answer is D, but I don't recognize that formula.
It is clearly a linear function, or an arithmetic sequence.
a_n = 4 * 3n-1
That is a geometric sequence with
a = 4
r = 3
S_3 = 4(3^3-1)/(3-1) = 4(26/2) = 52
It is clearly a linear function, or an arithmetic sequence.
a_n = 4 * 3n-1
That is a geometric sequence with
a = 4
r = 3
S_3 = 4(3^3-1)/(3-1) = 4(26/2) = 52
1 answer