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Date November 2015 Marks available 2 Reference code 15N.2.hl.TZ0.4
Level HL only Paper 2 Time zone TZ0
Command term Solve Question number 4 Adapted from N/A

Question

A function is defined by \(f(x) = A\sin (Bx) + C,{\text{ }} - \pi  \le x \le \pi \), where \(A,{\text{ }}B,{\text{ }}C \in \mathbb{Z}\). The following diagram represents the graph of \(y = f(x)\).

Find the value of

(i)     \(A\);

(ii)     \(B\);

(iii)     \(C\).

[4]
a.

Solve \(f(x) = 3\) for \(0 \le x \le \pi \).

[2]
b.

Markscheme

(i)     \(A =  - 3\)     A1

(ii)     period \( = \frac{\pi }{B}\)     (M1)

\(B = 2\)     A1

 

Note:     Award as above for \(A = 3\) and \(B =  - 2\).

 

(iii)     \(C = 2\)     A1

[4 marks]

a.

\(x = 1.74,{\text{ }}2.97\;\;\;\left( {x = \frac{1}{2}\left( {\pi  + \arcsin \frac{1}{3}} \right),{\text{ }}\frac{1}{2}\left( {2\pi  - \arcsin \frac{1}{3}} \right)} \right)\)     (M1)A1

 

Note:     Award (M1)A0 if extra correct solutions eg \(( - 1.40,{\text{ }} - 0.170)\) are given outside the domain \(0 \le x \le \pi \). Do not award FT in (b).

[2 marks]

Total [6 marks]

b.

Examiners report

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

Syllabus sections

Topic 3 - Core: Circular functions and trigonometry » 3.6 » Algebraic and graphical methods of solving trigonometric equations in a finite interval, including the use of trigonometric identities and factorization.
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