连掷两次骰子得到的点数分别为m和n,记向量=(m,n)有: (1,1),(1,2),(1,3),(1,4),(1,5),(1,6) (2,1),(2,2),(2,3),(2,4),(2,5),(2,6) (3,1),(3,2),(3,3),(3,4),(3,5),(3,6) (4,1),(4,2),(4,3),(4,4),(4,5),(4,6) (5,1),(5,2),(5,3),(5,4),(5,5),(5,6) (6,1),(6,2),(6,3),(6,4),(6,5),(6,6),共36个基本事件 若<,>∈(0,],则m≥n,则满足条件的=(m,n)有: (1,1),(2,1),(2,2),(3,1),(3,2),(3,3) (4,1),(4,2),(4,3),(4,4),(5,1),(5,2) (5,3),(5,4),(5,5),(6,1),(6,2),(6,3) (6,4),(6,5),(6,6),共21个基本事件 则P== 故答案为: |