1

I am fairly new to discrete mathematics.

I came across a question where I have the following premises:

  1. $p \implies q$
  2. $q \implies r$
  3. $\neg r$

Based on the text, the answer is the following:

  1. $\neg q$ using Modus Tollens on 2, 3
  2. $\neg p$ using Modus Tollens on 1, 4

Before looking at the answer, I derived the conclusion in the following steps:

  1. $p \implies r$ using Hypothetical syllogism on 1, 3

  2. $\neg p$ using Modus Tollens on 3, 4

Would anyone be able to help me understand which kind of approach would be good to take and how should I decide when to use which approach?

Rahul Wadhwani
  • 111

0 Answers0