Lemmara logoLemmaraWorked solution

0606/13 May/Jun 2025, Question 12: Equation of the Tangent Line

Cambridge IGCSE Additional Mathematics 0606 · Paper 13 (Non-calculator) · Non-calculator · 6 marks

اقرأ هذا الحل مشروحاً بالعربي ←

The question, in short

Curve y = 4/x² + ax + 7 has normal x + 4y = b at x = 2. Find constants a and b.

Summarised in our own words. Use the official paper for the exact wording and any diagrams.

Solution · 6 marks

  1. 1dy/dx = −8/x³ + a
  2. 2At x = 2: dy/dx = −1 + a = a − 1
  3. 3Normal gradient = −1/4, so tangent gradient = 4: a − 1 = 4, a = 5
  4. 4At x = 2: y = 4/4 + 10 + 7 = 18
  5. 5b = 2 + 4(18) = 74

Answera = 5, b = 74

Stuck on a step? Read the free lesson: Equation of the Tangent Line

Practise more equation of the tangent line questions

Real 0606 past-paper questions, marked on your working like the exam, with a worked solution for every part.

Practise free on Lemmara

More past-paper questions on equation of the tangent line

Also searched as: 0606/13/M/J/25 · 0606_s25_qp_13 · 0606 s25 13 · question 12.
Lemmara is an independent study tool, not affiliated with or endorsed by Cambridge International Education. The worked solutions are Lemmara’s own.