1)这将返回什么单位?(目标在脚下)

1) what units this is returning? (goal being in feet)

提供地球半径的任何单位.

Whatever units in which you supply the Earth's radius.

2)这个公式写的正确吗?

2) is this equation written the right way?

测试一下.您可以将结果与现有的Haversine公式实现进行比较，例如此.

Test it. You can compare your results with an existing Haversine formula implementation, like this one.