Math 223, Spring 2009
Midterm 1 Preparation
Your rst midterm is on Thursday, March 12. It is a closed-note, closed-book, open-brain, no-calculator
70-minute examination held during the regular class time. It will cover the material up to and including
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Math 223, Spring 2009
Final Review Solutions
(1) Determine whether the following congruences have a solution.
(a) x2 + 1 0 (mod 6911)
(b) x2 + 6x + 10 0 (mod 19)
Solution:
(a) Since 6911 3 (mod 4), this equation has no solutions by Quadratic Reciprocity P
Math 223, Spring 2009
Final Exam Preparation
Your nal exam is self-scheduled and can be taken any time during the nals period. It is a closed-note,
closed-book, open-brain, no-calculator 2.5-hour examination.
The exam is cumulative, and will have the same
Math 223, Spring 2009
Final Exam Solutions
Name:
Student ID:
Directions: Check that your test has 16 pages, including this one and the blank one on the
bottom (which you can use as scratch paper or to continue writing out a solution if you run out
room el
Math 223, Spring 09
Homework 12, due Wednesday, May 13
(1) What is the ciphertext that is produced when RSA encryption with public key (e, n) = (3, 2669) is used
to encrypt the message BEST W ISHES? Use the protocol A = 00, B = 01, ., Z = 25 and break you
Math 223, Spring 2009
Final Exam
Name:
Student ID:
Directions: Check that your test has 16 pages, including this one and the blank one on the
bottom (which you can use as scratch paper or to continue writing out a solution if you run out
room elsewhere).
Math 223, Spring 2009
Second Midterm Exam, April 23, 2009
Name:
Student ID:
Directions: Check that your test has 10 pages, including this one and the blank one on the
bottom (which you can use as scratch paper or to continue writing out a solution if you
Math 223, Spring 2009
Midterm 2 Preparation
Your second midterm is on Thursday, April 23. It is a closed-note, closed-book, open-brain, no-calculator
70-minute examination held during the regular class time. It will cover the material covered since the
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