# CMPSCI 250: Introduction to Computation

### David Mix Barrington

### Spring, 2012

# Homework Assignment #2

#### Posted Thursday 2 February 2012

#### Due on paper in lecture, Wednesday 15 February 2011.

There are twelve questions for 60 total points plus 10 extra credit.
All but one are from
the textbook, *
Mathematical Foundation for Computer Science*. Note that the book has
both Exercises and Problems -- make sure you are doing a Problem and not the
Exercise with the same number. The number in parentheses following each problem
is its individual point value.

Students are responsible for understanding and following
the academic honesty
policies indicated on this page.

Correction in purple made on 4 February 2012.

- Problem 1.7.2 (5) (You must find and justify expressions
using → and ¬ that are equivalent to x ∧ y, x ∨ y, x
⊕ y, and x ↔ y.)
- Problem 1.8.2 (5)
- Problem B-1 (10): Given the premise (x ⊕ y) ∧ (z
∨ x), give a deductive sequence proof of the compound proposition
y → (¬x ∧ z). Then, from the same premise, give a
separate deductive sequence proof of the compound proposition ¬z
→ x.
The first conclusion was originally given as y
→ (x ∧ ¬z).
- Problem 1.10.4 (5)
- Problem 1.10.5 (10 extra credit)
- Excursion 1.11, Writing Exercise #2 (5)
- Problem 2.3.2 (5)
- Excursion 2.4, Writing Exercise #1 (5)
- Problem 2.5.4 (5)
- Problem 2.6.2 (5)
- Problem 2.8.1 (5)
- Problem 2.9.2 (5) (Don't bother with the "explain carefully" part.)

Last modified 4 February 2012