Skip to content
Exercises · Q15

Q.Show that the statement “For any real numbers a and b, a2^2 = b2^2 implies that a = b” is not true by giving a counter-example.

Mahe DhseTextbookSubjectiveImportance★★★★★est
69% · 31/45 Questions
🔒 Locked · start free trial →

You're viewing a preview — the full solution, concept, methods & PYQ mapping are locked.

Start your 14-day free trial to unlock the full solution →

Claim to disprove: "For any real numbers a and b, a2=b2a^2 = b^2 implies that a=ba = b."

To disprove a universal implication, one counter-example suffices — a pair (a, b) satisfying the hypothesis (a2=b2a^2=b^2) but not the conclusion (a=ba=b).

Let a=2a = 2 and b=−2b = -2.

Then a2=22=4a^2 = 2^2 = 4 and b2=(−2)2=4b^2 = (-2)^2 = 4, so a2=b2a^2 = b^2 holds.

But a=2≠−2=ba = 2 \ne -2 = b, so a=ba = b fails. …

Unlock everything free for 14 days

  • Full step-by-step solutions
  • Concept-first explanations
  • Methods, shortcuts & mistakes
  • PYQ mapping + timed mock tests

Full access for 14 days. No credit card required.