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.
zh.xhopen.com（关于zh.xhopen.com的简介）-【copy_url:74ps.com】.y7b
zh.xhopen.com（关于zh.xhopen.com的简介）-【copy_url:74ps.com】.y7b
Natural Language
Math Input
Extended Keyboard
