Loading [MathJax]/jax/element/mml/optable/SuppMathOperators.js

User interface language: English | Español

Date May 2019 Marks available 2 Reference code 19M.2.SL.TZ1.S_8
Level Standard Level Paper Paper 2 Time zone Time zone 1
Command term Find Question number S_8 Adapted from N/A

Question

Let f(x)=2sin(3x)+4 for xR.

Let g(x)=5f(2x).

The function g can be written in the form g(x)=10sin(bx)+c.

The range of f is kf(x)m. Find k and m.

[3]
a.

Find the range of g.

[2]
b.

Find the value of b and of c.

[3]
c.i.

Find the period of g.

[2]
c.ii.

The equation g(x)=12 has two solutions where π ≤ x ≤ 4π3. Find both solutions.

[3]
d.

Markscheme

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

valid attempt to find range   (M1)

eg  ,  max = 6   min = 2,

2sin(3×π6)+4 and 2sin(3×π2)+4 ,   2(1)+4 and 2(1)+4,

k=2m=6      A1A1 N3

[3 marks]

a.

10 ≤ y ≤ 30      A2 N2

[2 marks]

b.

evidence of substitution (may be seen in part (b))       (M1)

eg   5(2sin(3(2x))+4)3(2x) 

b=6c=20   (accept 10sin(6x)+20 )     A1A1 N3

Note: If no working shown, award N2 for one correct value.

[3 marks]

c.i.

correct working      (A1)

eg   2πb

1.04719

2π6(=π3), 1.05     A1 N2

[2 marks]

c.ii.

valid approach     (M1)

eg   sin1(810)6x=0.9270.154549x=0.678147

Note: Award M1 for any correct value for x or 6x which lies outside the domain of f.

3.81974,  4.03424

x=3.82,  x=4.03  (do not accept answers in degrees)     A1A1 N3

[3 marks]

d.

Examiners report

[N/A]
a.
[N/A]
b.
[N/A]
c.i.
[N/A]
c.ii.
[N/A]
d.

Syllabus sections

Topic 2—Functions » SL 2.5—Modelling functions
Show 306 related questions
Topic 2—Functions » AHL 2.8—Transformations of graphs, composite transformations
Topic 2—Functions

View options