Graphs 9

4 marks · Normal

Let .

(a)

Expand to write it in the form .

[1 mark]

(b)

Differentiate your answer from part a with respect to .

[1 mark]

(c)

Calculate the gradient of the curve at .

[2 marks]

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(a) y = 3x^2 + 5x - 2

(b) 6x + 5

Common mistakes: Incorrect expansion; Incorrect use of product rule instead of expanding

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Marking points

B1 (a) · 1 mark · Expands correctly:

M1 (b) · 1 mark · Differentiates quadratic correctly to get (follow-through)

M2 (c) · 1 mark · Substitutes into derivative or follow-through from (b) (follow-through)

A1 (c) · 1 mark · Gives final answer (follow-through)

Worked solution