# How do u proof these?

by Altemicione
Tags: proof
 P: 2 1. Prove each of the following statements (assume that any conditioning event has positive probability). (a) If A is subset of B then P(B|A)=1 and p(A|B)=P(A)/P(B). (b) If A and B are mutually exclusive, then p(A|A u B)=((P(A)/((P(A)+P (B)) (C) P(A n B n C)= P(A|B n C) P( B|C) P(C) I"m really having problem in doing these. could someone help me out?
 Sci Advisor HW Helper P: 9,398 You just need to use the rules/identities of probability: P(X|Y) = P(XnY)/P(Y) and if A < B, then P(AnB)= P(A) since AnB=A, and P(AuB)=P(B) since AuB=B if A and B are mutually exclusive then P(AnB)=0 and P(AuB)=P(A)+P(B) the third follows from repeatedly applying the formula for conditional probability.
 P: 80 Moderator's note: please don't do others' homework for them
 Emeritus Sci Advisor PF Gold P: 16,099 How do u proof these? Have you been able to get anywhere on this, Altemicione?
 P: 7 Moderator's note: Same goes for you
 P: n/a Why can't we help a brother out?
 Sci Advisor HW Helper P: 9,398 you can, but just feeding the answers helps no one.
 P: 1,113 helps him pass his class so it helps one person then it helps his parents so they have to pay less for when he goes to college if he is still in high school so then the fincacial benefits spread through is family so in the end it could help a lot of people plus he prob learn how to do in class tomorrow but if u dont' have hw u get 0
 Emeritus Sci Advisor PF Gold P: 11,155 You think feeding him homework solutions makes him a better student and improves his odds of scoring higher in SATs (or whatever) ?
 P: 2,828 "If someone is hungry, don't give him a fish : teach him to fish !" who said that ?
 Sci Advisor HW Helper P: 9,398 Probably Gandhi
 Math Emeritus Sci Advisor Thanks PF Gold P: 39,300 "If you give a man a fish, he will eat for a day. If you teach a man to fish, he will never work another day in his life!"
HW Helper
P: 2,002
 Quote by HallsofIvy "If you give a man a fish, he will eat for a day. If you teach a man to fish, he will never work another day in his life!"
Or:

If you give a man a fish he will eat for a day. If you teach a man to fish he will drink beer, tell lies and wear a stupid hat.
 P: 2,828 Thanks you all for answering my "off-topic" question ! (although Galileo's version looks suspicous to me (^_^)
Emeritus