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Date May 2017 Marks available 4 Reference code 17M.2.hl.TZ1.2
Level HL only Paper 2 Time zone TZ1
Command term Find Question number 2 Adapted from N/A

Question

The curve C is defined by equation xylny=1, y>0.

Find dydx in terms of x and y.

[4]
a.

Determine the equation of the tangent to C at the point (2e, e)

[3]
b.

Markscheme

y+xdydx1ydydx=0     M1A1A1

 

Note:     Award A1 for the first two terms, A1 for the third term and the 0.

 

dydx=y21xy     A1

 

Note:     Accept y2lny.

 

Note:     Accept yx1y.

 

[4 marks]

a.

mT=e21e×2e     (M1)

mT=e2     (A1)

ye=e2x+2e

e2xy+3e=0 or equivalent     A1

 

Note:     Accept y=7.39x+8.15.

 

[3 marks]

b.

Examiners report

[N/A]
a.
[N/A]
b.

Syllabus sections

Topic 6 - Core: Calculus » 6.2 » Implicit differentiation.

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