Question

Evaluate
\[\sum_{k=1}^{7}2^{k+3}\]

Answer 1

https://www.desmos.com/calculator

Answer 2

or you can do manually.

Answer 3

can i get it manually lol

Answer 4

yes, pretty easily.

Answer 5

2^4+2^5+2^6+2^7+2^8+2^9+2^10

Answer 6

16+32+64+128+256+512+1024

Answer 7

Or you can do it the tricky, backwards way. 2^11-2^4 is the same as what rosho posted.
That's just 2048-16, and it saves a lot of addition.

Answer 8

The way I do the previous problems is split the sigma into two parts and add them