Thread: New To Discrete Math - HELP :(

1. New To Discrete Math - HELP :(

hey guys, im taking discrete math for the first time this semester, and all i can say is that i've been lost since the first day of class. sadly, i need this class for my major so i can't afford to fail/drop :/ I have my first quiz tommorrow and I'm 99% sure im going to fail so if you guys think you could help me out that'd be swell

the biggest problem i have with are proofs. im completely clueless in this subject. this is an example problem:

Suppose that A, B, and C are sets such that A (subset) B and B (subset) C. Show that A (subset) C.

the (subset)'s are the underlined C's but i just dont know how to put them in here. I understand that since A is a subset of B and B is a subset of C then obviously A is a subset of C. I just dont know how to prove that :\

2. Suppose that A implies B and B implies C then A implies C.
If x belongs to A then x belongs to B. (by definition of subset).
If x belongs to B then x belongs to C.
Therefore, If x belongs to A then x belongs to C, which means that A is a subset of C.

3. ahh thank you. for some reason i thought i would have to write a whole lot more than that lol