Discrete Math Help - Topic

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Jun 12 2013 01:44am

Quote (mcfighter @ 12 Jun 2013 05:45)

This is on logic, sets, proof, etc...
Any help is appreciated. and i need it within a few hours please

Let A, B, and C be any three sets and consider this sentence
a) If A ∪ B = A ∪ C then B = C Prove that this statement is false, (Give a counterexample )

take A = {1,2}, B = {1}, C = {2}

Write the converse of the above statement and illustrate through an example that it is true

not sure but i assume what is wanted is to show: if B=C then A u B = A u C which is quite trivial
if it is something different, please tell

What is the value of x after each of the following are encountered in a computer program if x = 1 before the statement is reached. Explain please

(a) if 2 + 3 = 5 AND 3 + 4 = 7 then x:= x + 1

both 2+3=5 and 3+4=7 are true, so x will be 2

(b) if 2 + 3 = 6 XOR 3 + 4 = 7 then x:= x + 1

xor requires that one is true and the other is false
which is the case because 2+3=/=6 (ie false) and 3+4=7 is true, so here too x will be 2

Thanks, if wanted fg will be given.