SPM 2017 Add Maths Paper 2, Question 2Differentiation

Solved on video in English and Bahasa Melayu · 7 marks · Form 5, Differentiation · 4:56 video

The question

It is given that the equation of a curve is y = 5/x². (a) Find the value of dy/dx when x = 3. (b) Hence, estimate the value of 5/(2.98)².

[7 marks]

Step 1

Write y = 5/x² = 5x⁻²

Why this step

The power rule only works on x raised to a power. Writing 5/x² as 5x⁻² lets us differentiate it straight away.

6 more steps, each with the reason for it, in the full solution

Final answer

(a) dy/dx = −10/27; (b) 5/(2.98)² ≈ 0.5630

Where students lose marks

Watch out: δx = 2.98 − 3 = −0.02, not +0.02, and add δy to y. δy alone is not the estimate.

Watch every step of this question solved on video (4:56), with the reason behind each step and a box that checks your own answer.

No card. Every past-year question on video, in English and BM.