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WMA11/01 Jun 2019, Question 1: Differentiating Polynomials

Pearson Edexcel International AS Level Mathematics · Pure Mathematics 1 (WMA11) · Calculator · 6 marks

The question, in short

Differentiate the given curve equation and use the result to find the tangent line at point P(4, −3).

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

Part (a) · 3 marks

Find dy/dx of y = (1/8)x³ − 24/√x + 1 in simplest form.

  1. 1y = (1/8)x³ − 24x^(−1/2) + 1
  2. 2dy/dx = (1/8)(3x²) − 24(−½)x^(−3/2)
  3. 3dy/dx = (3/8)x² + 12x^(−3/2)

Answerdy/dx = (3/8)x² + 12x^(−3/2)

Part (b) · 3 marks

Find the tangent to C at P(4, −3), giving it as y = mx + c.

  1. 1At x = 4: dy/dx = (3/8)(16) + 12(4)^(−3/2) = 6 + 1.5 = 7.5
  2. 2y + 3 = 7.5(x − 4)
  3. 3y = 7.5x − 33

Answery = 7.5x − 33

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Also searched as: WMA11 June 2019 · WMA11/01 · wma11 jun19 · IAS Maths Pure Mathematics 1 June 2019 · question 1.
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