Answer:
Option a.[tex]\sum_{k=0}^{k=3}(-2)^{3-k}[/tex].
Step-by-step explanation:
In this question the given series is -8 + 4 - 2 + 1...
which can be written as [tex]-2^{3}+2^{2}-2^{1}+2^{0}[/tex]
Or [tex]-2^{(3-0)}+2^{(3-1)}-2^{(3-2)}+2^{(3-3)}[/tex]
Here the expression are ranging from 0 to 3.
Now we can see that it's an exponential series
Now we write it in the form of sigma notation
[tex]=\sum_{k=0}^{k=3}(-2)^{3-k}[/tex]
So the answer is Option a.[tex]\sum_{k=0}^{k=3}(-2)^{3-k}[/tex]
