CP18-20
The problems in this problem set cover lecture [C17 = quiz review], C18, C19, C20
1. The operation ⊕ is defined for two Boolean variables A, B as follows:
A⊕B = B A BA +
Draw the truth table for A⊕B
2. What are the minterms in the expression A⊕B⊕C?
Hint: Use a dummy variable D for A⊕B, apply the Boolean algebra theorems, then
replace D with A⊕B and repeat the process.
3. Convert the following English statements into formal propositions.
a. The killer touched both the candlestick and the wrench
b. There are exactly 2 sets of fingerprints on the candlestick.
c. Joe touched either the candlestick or the wrench, but not both.
d. George only touched the candlestick.
e. George saw Hannah touch the wrench.
f. Hannah touched all the weapons that George touched.
g. Hannah saw Joe touch the candlestick
Given that there is only one killer, use resolution to identify the killer.
4. Provide a Direct Proof of the following, where a, b, and c are integers
If a|b and b|c, then a|c
Hint: definition of “ | “ (Divisible) is given in lecture 20.
5. Prove using induction that P(n) = P(n-1) + P(n-2), where P(n) is a Fibonacci number.
Hint: What are Fibonacci numbers? That will help you identify the base case.
6. Prove using induction that if p does not divide any of the numbers a1, a2, a3, …, an
(i.e., p is not a common divisor for a1, a2, a3, …, an) ;then p does not divide a1*a2*a3*
…*an
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