Uh oh! Wolfram|Alpha doesn't run without JavaScript.
Please enable JavaScript. If you don't know how, you can find instructions
here
.
Once you've done that, refresh this page to start using Wolfram|Alpha.
100+Sum[2 * 400e^((-(2k)^2)/4), {k, 0,3}] - 760
100+Sum[2 * 400e^((-(2k)^2)/4), {k, 0,3}] - 760
Natural Language
Math Input
Extended Keyboard
