If we calculate the tangent of this angle, we now have a value that corresponds to the ratio between the displacement on the X axis versus the distance away from the viewer on the Y.
If we calculate the tangent of this angle, we now have a value that corresponds to the ratio between the displacement on the X axis versus the distance away from the viewer on the Y.
如果我们计算这个角的正切，我们就可以知道相应的比值：X轴上的位置相对于Y轴上的观察者的距离的比值。