C-08-Q168mediumsingle_mcqIn 0<θ<2π0 < \theta < 2\pi0<θ<2π, the equation sec2θ+tan2θ=3\sec^{2}\theta + \tan^{2}\theta = 3sec2θ+tan2θ=3 gives cos2θ\cos^{2}\thetacos2θ equal to —a12\dfrac{1}{2}21b13\dfrac{1}{3}