The intensity, I I\,I units, of polarised light passing through a rotating filter is modelled by
I=I0cos2θI = I_0 \cos^2\thetaI=I0cos2θ
where I0 I_0\,I0 is the maximum intensity and θ \theta\,θ is the angle of the filter in radians.
In one experiment the maximum intensity is measured as I0=12I_0 = 12I0=12 units.
Determine all the values of θ \theta\,θ in the interval 0≤θ≤2π 0 \leq \theta \leq 2\pi\,0≤θ≤2π for which I=9I = 9I=9 units. Give your answers as exact multiples of π\piπ.
State the values of θ \theta\,θ in the interval 0≤θ≤2π 0 \leq \theta \leq 2\pi\,0≤θ≤2π at which the model predicts the maximum intensity.
225 exam-style questions on WJEC A Level Maths 3.5 Trigonometry (A-level only), covering 3.5.1 Trigonometry (A-level only), 3.5.2 Trigonometry (A-level only), 3.5.3 Trigonometry (A-level only), 3.5.4 Trigonometry (A-level only), 3.5.5 Trigonometry (A-level only), 3.5.6 Trigonometry (A-level only), 3.5.7 Trigonometry (A-level only), and 3.5.8 Trigonometry (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.