# SPM 2021 Add Maths Trial Paper (Selangor) – Paper 1 (Question 10)

Question 10:
(a) Given the gradient of the tangent to the curve y = x2 (3 + px) is -3 when x = -1.
Find the value of p. [2 marks]

(b) Volume, V cm3, of a solid is given by $V=8\pi {r}^{2}+\frac{2}{3}\pi {r}^{3}$ , r is the radius. Find the approximate change in V, in terms of π, if r increases from 3 cm to 3.005 cm. [3 marks]

Solution:
(a)

(b)