CSCI 250 Spring 2013Discrete Structures Archived Class

Homework 3

• Problems are taken from the textbook unless otherwise noted.
• For full credit, provide context for each problem, show all calculations, and justify all answers by providing enough comments to explain your reasoning.
• You will lose a significant amount of credit if you do not provide context, calculations, and justifications for a problem.
• Numbers and/or algebra by themselves are not enough. A correct answer with no justification will be worth no more than half credit, and sometimes much less than that.
• Precision is very important. You cannot skip steps, make guesses, or use flawed logic. Any of these things can lead to incorrect answers.
• Homework assignments must be very neatly written or typeset (e.g. using Word or OpenOffice).
• You must indicate any assistance/collaboration you had on an assignment as specified on the Policies page.

Details

SectionProblemNotes
1.310dFor this and similar problems:
• List the variable columns and rows in the same order as the examples in the textbook.
• Show intermediate columns as necessary.
• A truth table is not a proof. Clearly state why the truth table proves what is asked.
• 14
16Read the paragraph before the problem.
30Begin by realizing that it can only be false if the premise is true but the conclusion is false. Then argue that if the conclusion is false, the premise is too.
1.414Justify your answers by providing an example, counter example, and/or brief explanation.
36
50Define a universe of discourse and choose statements P and Q on that universe such that the given statements have different truth values. Notice that 49 is similar.