2.某人对一目标接连射击三次,设 _(1)= 第i次命中目标}, i=1,2,3 _(1)= 恰好j次命中目标},-|||-hat (j)=0,1,2,3 _(E)= 至少k次命中目标}, =0,1,2,3.-|||-(1)由A1,A2,A3表示B2:(2)由B0,B1,B 2,B3表示 _(1)-(C)_(3)