plumiProof by contradiction: Edexcel A‑Level Maths questions
Edexcel A-Level Maths past-paper questions on 1.3 Proof by contradiction, 2010–2025, with mark schemes and examiner’s reports where available. Add MadAsMaths questions to your practice, or browse them separately by topic and difficulty.
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All 5 questions on Proof by contradiction, as a list
- June 2024, Pure 1, Q15 (6 marks): (i) Show that k 2 – 4k + 5 is positive for all real values of k. (2) (ii) A student was asked to prove by contradiction that “There are no positive integers x a
- June 2023, Pure 2, Q15 (3 marks): A student attempts to answer the following question: Given that x is an obtuse angle, use algebra to prove by contradiction that sin x – cos x 1 The student s
- June 2022, Pure 1, Q7 (5 marks): (i) Given that p and q are integers such that pq is even use algebra to prove by contradiction that at least one of p or q is even. (3) (ii) Given that x and y
- November 2021, Pure 1, Q15 (6 marks): (i) Use proof by exhaustion to show that for n ∈ , n 4 (n + 1) 3 > 3 n (2) (ii) Given that m3 + 5 is odd, use proof by contradiction to show, using algebra,
- November 2020, Pure 1, Q16 (4 marks): Prove by contradiction that there are no positive integers p and q such that 4 p2 − q2 = 25 (4)
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