MATH312 December 2012
• Q1 (a) • Q1 (b) • Q1 (c) • Q1 (d) • Q1 (e) • Q1 (f) • Q1 (g) • Q2 (a) • Q2 (b) • Q2 (c) • Q2 (d) • Q3 • Q4 • Q5 •
Question 01 (e)
Short answer questions: Each question carries 6 marks, your answers should quote the results being used and show your work.
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Make sure you understand the problem fully: What is the question asking you to do? Are there specific conditions or constraints that you should take note of? How will you know if your answer is correct from your work only? Can you rephrase the question in your own words in a way that makes sense to you?
If you are stuck, check the hint below. Consider it for a while. Does it give you a new idea on how to approach the problem? If so, try it!
We need to find the inverse of 7 modulo 13, possible since they are coprime. Use the Euclidean algorithm.
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Following the hint, we compute the inverse of 7 modulo 13. Then
and back substituting gives .
Thus, the inverse of 7 modulo 13 is 2. Hence which completes the question.
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MER QGH flag, MER QGQ flag, MER QGS flag, MER RT flag, MER Tag Euclidean algorithm, MER Tag Modular arithmetic, Pages using DynamicPageList parser function, Pages using DynamicPageList parser tag