Question

Please help with this sigma notation question?
What is the series in sigma notation? -5 + (-1) + 3 + 7 + 11?

Answer 1

What's the common difference between the numbers?

Answer 2

There adding 4 each time?

Answer 3

Would the answer be
5
Z (4i - 9)
i = 1

Answer 4

Yes. You could also start at i=0 and say
4
Z (4i-5)
i=0
if you wanted to, but yours works just as well. Good job!

Answer 5

Thanks! Can u help me with one more to?

Answer 6

Sure.

Answer 7

Which represents the series in sigma notation? 1 + 1/2 + 1/4 + 1/8 + 1/16 + 1/32 +1/64?

Answer 8

The common difference would be that there all being times by 2 to get the next number

Answer 9

Would the answer be
7
Z 1/2^( i + 1)
i = 1

Answer 10

You've got the right idea, but your exponent is wrong. When you plug in i=1, you get the answer 1/4 instead of 1.

Answer 11

None of my answers have 1/4 in them.
There all 1/2 or 2