Java 我如何找到一条线的反正切？
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How do I find the inverse tangent of a line?
提问by Skizit
I've got a line (x1,y1) and (x2,y2). I'd like to use tan inverse to find the angle of that line, how would I do so in java?
我有一条线 (x1,y1) 和 (x2,y2)。我想使用 tan inverse 来找到那条线的角度，我将如何在 Java 中这样做？
I'd like to see what angle the line makes in relation to x1,y1
我想看看这条线与 x1,y1 的夹角
采纳答案by Gedrox
You need
你需要
Math.toDegrees(Math.atan((y2-y1)/(x2-x1)))
Math.toDegrees(Math.atan((y2-y1)/(x2-x1)))
Do notice exception when x1=x2.
当 x1=x2 时注意异常。
回答by stacker
This post Angle between 2 pointshas an example using atan().
回答by Josh Lee
Use the Math.atan2function. It is like arctan but knows about x and y coordinates, so it can handles lines that are horizontal, vertical, or pointing in other directions -- arctan's range of -pi/2 through pi/2 will not give the correct answer for some lines.
使用该Math.atan2功能。它类似于 arctan 但知道 x 和 y 坐标，因此它可以处理水平、垂直或指向其他方向的线——arctan 的 -pi/2 到 pi/2 的范围不会给出某些线的正确答案.
