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.
如何避免无形干扰因素咨询【�83�83�978�9755�9E88�9E√转ihbwel戴69Z
Natural Language
Math Input
Extended Keyboard
Examples
Upload
Random
