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1.4 Trigonometry

1.4 Trigonometry

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Question 25

The intensity I I\,I of a laser beam passing through a specific optical filter is modeled by the equation I=5cos⁡2α+sin⁡2αI = 5\cos^2 \alpha + \sin 2\alphaI=5cos2α+sin2α, where α \alpha\,α is the angle of incidence.

a.

Given that I=2I = 2I=2, show that

2tan⁡2α−2tan⁡α−3=0 2\tan^2 \alpha - 2\tan \alpha - 3 = 0 2tan2α−2tanα−3=0
[3]
b.

Hence, find all possible values of α \alpha\,α in the range 0<α<2π 0 < \alpha < 2\pi\,0<α<2π for which the intensity is 2 units. Give your answers to two decimal places.

[4]
c.

Determine the values of x x\,x in the interval 0<x<π3\displaystyle 0 < x < \frac{\pi}{3}0<x<3π​ such that

5cos⁡2(3x+π4)+sin⁡(6x+π2)=2 5\cos^2 \left( 3x + \frac{\pi}{4} \right) + \sin \left( 6x + \frac{\pi}{2} \right) = 2 5cos2(3x+4π​)+sin(6x+2π​)=2

Give your answers to one decimal place.

[3]
Markscheme

1.4 Trigonometry Questions

  1. A Level
  2. /Maths
  3. /1.4 Trigonometry

84 exam-style questions on CCEA A Level Maths 1.4 Trigonometry, covering 1.4.1 Trigonometry, 1.4.2 Trigonometry, 1.4.3 Trigonometry, 1.4.4 Trigonometry, 1.4.5 Trigonometry, 1.4.6 Trigonometry, and 1.4 Trigonometry. Each one has a worked solution and a mark scheme showing where the marks go.

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