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Find the first and second derivatives of f.

Read the idea, work independently, then explain what changed.

TOPIC 01

2021 JM02

Do not retain the constant −5 in f′.

Try it. Leave your reasoning visible.

Use one hint at a time. A correction explains what changed, not just the final answer.

01 / Standard#Your turn

Find the first and second derivatives of f.

f(x)=2x3−9x2+12x−5f(x)=2x^3-9x^2+12x-5

Official paper · jm02-2021 · 2(a)(i) · PDF 4

Official original and suggested answers ↗ · Suggested answer PDF page 8

Skills and prerequisite lessons

Working and explanation

BUILD THE REASONING

Hint 1
Differentiate each polynomial term.
Hint 2
Differentiate the first derivative once more.
Worked solution
  1. Use the power rule.

    f′(x)=6x2−18x+12f'(x)=6x^2-18x+12
  2. Constants vanish when differentiated.

    f′′(x)=12x−18f''(x)=12x-18

f′(x)=6x²−18x+12; f″(x)=12x−18.

Checks and common pitfalls: Do not retain the constant −5 in f′.

Reasoning checklist · self / teacher assessment
  • Teaching assessment checklist, independently authored. Use the original paper for official marks.
  • Use the power rule.
    f′(x)=6x2−18x+12f'(x)=6x^2-18x+12
  • Constants vanish when differentiated.
    f′′(x)=12x−18f''(x)=12x-18

Think first. Reveal a hint when the class is ready.

Focus on one question

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Curriculum and source notes ↗