Answer:
The correct option is C. 5
Therefore,

Step-by-step explanation:
Simplify

Solution:
Using Identity

So in the given expression

Therefore,

Therefore,

Answer:
Step-by-step explanation: a, c, and e
Answer:
Your answer is correct. The series is a geometric series with common ratio -1/4 and first term 40. So each term is:
an = 40 (-1/4)^(n−1)
So the sum of the first 10 terms is:
∑(n=1 to 10) [ 40 (-1/4)^(n−1) ]
Answer:
a
Step-by-step explanation: