An optical sensor measures the flux F F\,F of light entering an aperture at a small angle ϕ \phi\,ϕ radians. The flux is modelled by the expression:
F=1−cos(14ϕ)ϕsin(7ϕ) F = \frac{1 - \cos(14\phi)}{\phi \sin(7\phi)} F=ϕsin(7ϕ)1−cos(14ϕ)Using small angle approximations, show that for small, non-zero values of ϕ\phiϕ,
F≈A F \approx A F≈Awhere A A\,A is a constant to be determined.