... (2.8), P(X = -Go)= P(Y = -co)=O Since (X= - a,Y~y)c(X=-a) and (XIX,YI-a)c(Y=-co) and by Eq. (1 .D), we have P(X = -a, Y I y) = Fxy(-m, y) = 0 P(X I X, Y = - m) = FxY(x, ... there is a closed path between a and b if s, and s, or s, and s, are closed. From Fig. 1-5 (d), we see that there is a closed path between a and b if either s, and s, are closed or s, is ... 1 - 0.95 = 0.05 PROBABILITY [CHAP 1 1.25. For any three events A,, A,, and A,, show that P(Al u A, u A,) = P(Al) + P(A,) + P(A,) - P(A, n A,) - P(Al n A,) - P(A,...