Skip to main content
A-LevelFurther MathematicsProof by induction9231/12 · Oct/Nov 2018 · Q68 Marks

It is given that y = eˣu, where u is a function of x. The rth derivatives dʳy/dxʳ and dʳu/dxʳ are denoted by y⁽ʳ⁾ and u⁽ʳ⁾ respectively. Prove by mathematical induction that, for all positive integers n, y⁽ⁿ⁾ = eˣ ((ⁿ₀) u + (ⁿ₁) u⁽¹⁾ + (ⁿ₂) u⁽²⁾ + ... + (ⁿᵣ) u⁽ʳ⁾ + ... + (ⁿₙ) u⁽ⁿ⁾). [You may use without proof the result (ᵏᵣ) + (ᵏᵣ₋₁) = (ᵏ⁺¹ᵣ)].

Mark scheme

Marking points from the official mark scheme (Oct/Nov 2018). The mark or mark type is shown in brackets.

  1. [M1A1] Shows base case using product rule
  2. [B1] States inductive hypothesis.
  3. [M1] Differentiates using product rule
  4. [M1A1] Shows application of (k r) + (k r-1) = (k+1 r).
  5. [B1] Shows reasoning for first and last term correctly
  6. [A1] States conclusion.

Write your answer and get it marked

On Oracle Prep you can write or photograph your own answer and have it marked by AI against this mark scheme, with feedback on what you missed.

Sign up free →

About this question

Topic
Proof by induction, A-Level Further Mathematics (syllabus 9231). Structured question, 8 marks.
Source
A-Level Further Mathematics, Oct/Nov 2018 Paper 1 Variant 2, question 6.

Questions and mark schemes are from past examination papers and remain the copyright of the exam board. How Oracle Prep builds its content

Related Further Mathematics questions

© 2026 Oracle Prep