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.
d/da e^a/(e^a + e^b + e^c)
d/da e^a/(e^a + e^b + e^c)
Natural Language
Math Input
Extended Keyboard