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Date May 2019 Marks available 9 Reference code 19M.1.AHL.TZ1.H_7
Level Additional Higher Level Paper Paper 1 (without calculator) Time zone Time zone 1
Command term Find Question number H_7 Adapted from N/A

Question

Find the coordinates of the points on the curve y3+3xy2x3=27 at which dydx=0.

Markscheme

* This question is from an exam for a previous syllabus, and may contain minor differences in marking or structure.

attempt at implicit differentiation      M1

3y2dydx+3y2+6xydydx3x2=0      A1A1

Note: Award A1 for the second & third terms, A1 for the first term, fourth term & RHS equal to zero.

substitution of dydx=0      M1

3y23x2=0

y=±x      A1

substitute either variable into original equation       M1

y=xx3=9x=39   (or  y3=9y=39)      A1

y=xx3=27x=3   (or  y3=27y=3)      A1

(39,39) , (3, −3)      A1

[9 marks]

Examiners report

[N/A]

Syllabus sections

Topic 5 —Calculus » SL 5.3—Differentiating polynomials, n E Z
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