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.
simplify (x' / (1 - v/c) + x' / (1 + v/c)) / 2
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random