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Date November 2017 Marks available 5 Reference code 17N.1.hl.TZ0.6
Level HL only Paper 1 Time zone TZ0
Command term Solve and Hence or otherwise Question number 6 Adapted from N/A

Question

Sketch the graph of y=13xx2, showing clearly any asymptotes and stating the coordinates of any points of intersection with the axes.

N17/5/MATHL/HP1/ENG/TZ0/06.a

[4]
a.

Hence or otherwise, solve the inequality |13xx2|<2.

[5]
b.

Markscheme

N17/5/MATHL/HP1/ENG/TZ0/06.a/M

correct vertical asymptote     A1

shape including correct horizontal asymptote     A1

(13, 0)     A1

(0, 12)     A1

 

Note:     Accept x=13 and y=12 marked on the axes.

 

[4 marks]

a.

METHOD 1

N17/5/MATHL/HP1/ENG/TZ0/06.b/M

13xx2=2     (M1)

x=1    A1

(13xx2)=2     (M1)

 

Note:     Award this M1 for the line above or a correct sketch identifying a second critical value.

 

x=3     A1

solution is 3<x<1     A1

 

METHOD 2

|13x|<2|x2|, x2

16x+9x2<4(x24x+4)     (M1)A1

16x+9x2<4x216x+16

5x2+10x15<0

x2+2x3<0     A1

(x+3)(x1)<0     (M1)

solution is 3<x<1     A1

 

METHOD 3

2<13xx2<2

consider 13xx2<2     (M1)

 

Note:     Also allow consideration of “>” or “=” for the awarding of the M mark.

 

recognition of critical value at x=1     A1

consider 2<13xx2     (M1)

 

Note:     Also allow consideration of “>” or “=” for the awarding of the M mark.

 

recognition of critical value at x=3     A1

solution is 3<x<1     A1

[5 marks]

 

b.

Examiners report

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

Syllabus sections

Topic 2 - Core: Functions and equations » 2.7 » Solutions of g(x) .

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