实验3.4(大圆距离):假设(x1,y1)和(x2,y2)为两点的经度和维度,两点之间的大圆距离可以用如下公式计算:D=radius*arccos(sin(x1)*sin(x2)+cos(x1)*cos(x2)*cos(y1-y2))编写程序,提示用户输入两点的经度和维度(负值表示东经或北纬),显示两点的球面距离,地球半径radius=6371.01km,例如:39.55,-116.2541.5,87.37The distance between the two points is:10691.79183231593km