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Date May 2019 Marks available 3 Reference code 19M.1.SL.TZ2.S_7
Level Standard Level Paper Paper 1 (without calculator) Time zone Time zone 2
Command term Find Question number S_7 Adapted from N/A

Question

Consider the graph of the function f ( x ) = 2 sin x ,  0 ≤ x < 2 π . The graph of f intersects the line y = 1 exactly twice, at point A and point B. This is shown in the following diagram.

Consider the graph of  g ( x ) = 2 sin p x , 0 ≤ x < 2 π , where p > 0.

Find the greatest value of p such that the graph of g does not intersect the line y = 1 .

Markscheme

recognizing period of  g is larger than the period of  f         (M1)

eg   sketch of g with larger period (may be seen on diagram), A at  x = 2 π ,

      image of A when  x > 2 π ,   7 π 6 2 π ,   2 sin ( 2 π p ) = 1 ,   7 π 6 × k = 2 π

correct working       (A1)

eg    7 π 6 1 p = 2 π ,   2 π p = 7 π 6 ,   12 7

p = 7 12     ( accept p < 7 12 or p 7 12 )        A1  N2

[3 marks]

Examiners report

[N/A]

Syllabus sections

Topic 3— Geometry and trigonometry » SL 3.7—Circular functions: graphs, composites, transformations
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Topic 3— Geometry and trigonometry

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