Use the identity cos2θ+sin2θ=1\cos^2\theta + \sin^2\theta = 1cos2θ+sin2θ=1 to prove that sec2θ=1+tan2θ\sec^2\theta = 1 + \tan^2\thetasec2θ=1+tan2θ.
Solve, for 0≤θ≤2π0 \leq \theta \leq 2\pi0≤θ≤2π, the equation,
sec2θ+3tan2θ=13 \sec^2\theta + 3\tan^2\theta = 13 sec2θ+3tan2θ=13Give your answers in terms of π\piπ.