P((E2C∩E3C)/E1)=P(E1)P(E1∩(E2C∩E3C))
=P(E1)P(E1)−{P(E1∩E2)+P(E1∩E3)−P(E1∩E2∩E3)}
=P(E1)P(E1)−P(E1∩E2)−P(E1∩E3)−0
=1−P(E1)P(E1∩E2)−P(E1)P(E1∩E3) = 1 - P(E2/E1)−P(E3/E1)
=1−P(E2)−P(E3)
=P(E3C)−P(E2) or P(E2C)−P(E3)