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Date May Specimen paper Marks available 5 Reference code SPM.2.AHL.TZ0.9
Level Additional Higher Level Paper Paper 2 Time zone Time zone 0
Command term Find Question number 9 Adapted from N/A

Question

Consider the graphs of y = x 2 x 3  and y = m ( x + 3 ) m R .

Find the set of values for m such that the two graphs have no intersection points.

Markscheme

METHOD 1

sketching the graph of  y = x 2 x 3 ( y = x + 3 + 9 x 3 )      M1

the (oblique) asymptote has a gradient equal to 1 

and so the maximum value of m is 1      R1

consideration of a straight line steeper than the horizontal line joining (−3, 0) and (0, 0)      M1

so m > 0      R1

hence 0 < m ≤ 1      A1

 

METHOD 2

attempting to eliminate y to form a quadratic equation in  x        M1 

x 2 = m ( x 2 9 )

( m 1 ) x 2 9 m = 0       A1

 

EITHER

attempting to solve 4 ( m 1 ) ( 9 m ) < 0 for  m        M1 

 

OR

attempting to solve  x 2 < 0 ie  9 m m 1 < 0 ( m 1 )  for  m        M1

 

THEN

0 < m < 1       A1

a valid reason to explain why  m = 1  gives no solutions eg if  m = 1 ,

( m 1 ) x 2 9 m = 0 9 = 0 and so 0 <  m ≤ 1      R1

 

 

[5 marks]

Examiners report

[N/A]

Syllabus sections

Topic 2—Functions » AHL 2.13—Rational functions
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