How can I re-write the sum's suing Sigma Notation for:

2 - 2^2 + 2^3 -2^4 +2^5

I know the reoccuring number is going to be 2 which goes to the right of the sigma. on the bottom of sigma it would be 1, and top of sigma would be 5 right?

Question

How can I re-write the sum's suing Sigma Notation for:

2 - 2^2 + 2^3 -2^4 +2^5

I know the reoccuring number is going to be 2 which goes to the right of the sigma.  on the bottom of sigma it would be 1, and top of sigma would be 5 right?

lilsis76 · Answer

|dw:1353786244962:dw|

anonymous · Answer

$$\sum_{n=0}^{4}2(-2)^n$$
is one way of writing it.

lilsis76 · Answer

oh. so that (-2), is that how it would go from negative to positive?

anonymous · Answer

expand what i wrote and check for yourself

lilsis76 · Answer

okay:

-2^0 = 0 *2 = 0
-2^1=-2*2=-4
-2^2=-4*2=-8
-2^3=-8*2=-16

lilsis76 · Answer

@cnknd  is this how it would go?

anonymous · Answer

ur doing the exponents wrong... this is basics...

lilsis76 · Answer

|dw:1353786706417:dw|okay the first one would be>....<   @cnknd