Answer:
an = 400*(1/2)^(n - 1) which is C is the most common answer.
Step-by-step explanation:
What did you have to do to get 400 as the first term?
There are two answers.
an = 400 * (1/2)^(n - 1)
an = 400 * (1/2)^n
Which one is the answer?
The answer is the one that leaves 400 as the first term.
a1 = 400*(1/2)^(n-1) should be the answer.
400*(1/2)^n is unfortunately sometimes used. In which case, the first term is a^0
A1 = 400 (1/2)^(n - 1) is the usual for that describes the series.
