As title,
想要打出"因為"的數學符號，卻不停失敗..
已經嘗試單獨一行 $\because$ ，依舊無法成功，但是刪除\because後，
內容是可以成功編輯的。
如圖所示：http://imgur.com/YMRABXu
然後複製了下方錯誤碼，google之後還是不知如何解決問題
附上錯誤碼：
$\because $ The control sequence at the end of the top line of your error
message was never \def'ed. If you have misspelled it (e.g., `\hobx'), type
`I' and the correct spelling (e.g., `I\hbox'). Otherwise just continue, and
I'll forget about whatever was undefined.
請問該從哪邊去改善這問題呢...QQ