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JEE Main 2021
Mathematical Reasoning
Mathematical Reasoning
Easy

Question

The negation of the statement “If I become a teacher, then I will open a school” is :

Options

Solution

Key Concepts and Formulas

  • Conditional Statement: A conditional statement "If p, then q" is denoted by pqp \to q.
  • Negation of a Conditional Statement: The negation of pqp \to q is given by pqp \land \sim q.
  • Logical Connectives:
    • \sim denotes negation (NOT)
    • \land denotes conjunction (AND)
    • \lor denotes disjunction (OR)
    • \to denotes implication (IF...THEN)

Step-by-Step Solution

Step 1: Define the propositions.

Let's define the following propositions: pp: I become a teacher. qq: I will open a school.

We are given the statement "If I become a teacher, then I will open a school", which can be represented as pqp \to q.

Step 2: Find the negation of the conditional statement.

We want to find the negation of the statement pqp \to q, which is denoted by (pq)\sim (p \to q). Using the formula for the negation of a conditional statement, we have: (pq)pq\sim (p \to q) \equiv p \land \sim q This means "p AND NOT q".

Step 3: Translate the negation back into English.

Now, we translate pqp \land \sim q back into English using the definitions of pp and qq: pp: I become a teacher. q\sim q: I will not open a school.

Therefore, pqp \land \sim q translates to "I will become a teacher and I will not open a school."

Common Mistakes & Tips

  • A common mistake is to confuse the negation of pqp \to q with pq\sim p \to \sim q or pq\sim p \lor q. Remember that (pq)pq\sim (p \to q) \equiv p \land \sim q.
  • Another mistake is to incorrectly translate the logical connectives back into English. Pay close attention to the meaning of "and" and "or".
  • Remember the equivalent form pqpqp \to q \equiv \sim p \lor q. Therefore, (pq)(pq)pq\sim(p \to q) \equiv \sim(\sim p \lor q) \equiv p \land \sim q (using De Morgan's Law).

Summary

We are given the statement "If I become a teacher, then I will open a school", which is represented as pqp \to q. We need to find the negation of this statement, (pq)\sim (p \to q). Using the formula (pq)pq\sim (p \to q) \equiv p \land \sim q, we find the negation to be "I will become a teacher and I will not open a school." This corresponds to option (A).

Final Answer The final answer is \boxed{I will become a teacher and I will not open a school}, which corresponds to option (A).

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