If you call this plus, then if you get a minus sign, you know that the velocity is in the opposite direction.

你若称此为正号，你若想要一个负号，你们知道的，相反方向的速度。

youdao

1 Similarly, if m is equal to either plus 1 or minus 1, py we would in turn call it the p y orbital, or the p x orbital.

类似的，如果m等于+1或，我们可以叫它，或者px轨道。

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