Answer:
:)
Step-by-step explanation:
For simplicity I will substitue for β.
In the first step I used the identity
And I factored out
Then it's just simple algebra to cancel till the 3rd step where we used another identity derived from the Pythagorean Theorem.
That's it!
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