Two support lines divide the convex hull into two parts, st and ts. From the image below we can know thatCeC答案窝(daanwo.com)-大学生作业答案及考资分享平台

凸包外部的一点x引出的两条支撑线xt，xs将凸包边界分成st和ts两部分，通过观察我们可以知道CeC答案窝(daanwo.com)-大学生作业答案及考资分享平台

AAny segment connecting x with a random point on ts will not intersect with any other boundary of the convex hull (ts上的任意一点与x相连都不会与凸包其他边界相交)CeC答案窝(daanwo.com)-大学生作业答案及考资分享平台

BAny segment connecting x with a random point on st will not intersect with any other boundary of the convex hull (st上的任意一点与x相连都不会与凸包其他边界相交)CeC答案窝(daanwo.com)-大学生作业答案及考资分享平台

CAny point on ts is invisible to x (ts上的任意一点都对于x不可见)CeC答案窝(daanwo.com)-大学生作业答案及考资分享平台

DAny point on st is visible to x (st上的任意一点都对于x可见)CeC答案窝(daanwo.com)-大学生作业答案及考资分享平台