Answer:8
Step-by-step explanation:
You find the average which is adding them all together then dividing by how many numbers you added.
The wording of this question is a bit confusing... You can't write a sequence in sigma notation, but rather a series or sum. I think the question is asking you to write the sum of the sequence,

which would be

in sigma notation.
To do this, notice that the denominator in each term is a power of 2, starting with
and ending with
. So in sigma notation, this series is

Answer:
10.4^2 = 108.16
Step-by-step explanation:
10.4^2 = 10.4 * 10.4
10.4 * 10.4 = (10 * 10.4) + (0.4 * 10.4)
(10 * 10.4) + (0.4 * 10.4) = (104) + (4.16)
(104) + (4.16) = 108.16