Question

please help finding the value?

Answer 1

Do you understand the notation they are using?

Answer 2

I understand there is a sequence an i=1 and I need to figure oyt what i3 is but I must be doing something wrong because Im not getting any of those ansers

Answer 3

do I add and then mutiply in the sequence?

Answer 4

\[\sum_{i-1}^{3}\]
This means you have to put the value of i in

\[4\times \frac{ 1 }{ 2 }^i-1\]

one by one and add them

Answer 5

till i=3

Answer 6

Then I would asume 7/2 but it can't be that simple right

Answer 7

ohh srry
\[4\times (\frac{ 1 }{ 2 })^{(i-1)}\]

Answer 8

no the anser is 7

Answer 9

the expansion of this notation is
\[4\times (\frac{1}{2})^{(1-1)}+4\times (\frac{1}{2})^{(1-2)}+4\times (\frac{1}{2})^{(1-3)}\]

Answer 10

thank you