JEE Main 20209 Jan, Evening shiftMathematicsMediumTrigonometry118× since 2002If x=∑n=0∞(−1)ntan2nθx = \sum\limits_{n = 0}^\infty {{{\left( { - 1} \right)}^n}{{\tan }^{2n}}\theta }x=n=0∑∞(−1)ntan2nθ and y=∑n=0∞cos2nθy = \sum\limits_{n = 0}^\infty {{{\cos }^{2n}}\theta }y=n=0∑∞cos2nθ for 0 < θ\thetaθ < π4{\pi \over 4}4π, then :AOption A. x(1 + y) = 1BOption B. y(1 – x) = 1COption C. y(1 + x) = 1DOption D. x(1 – y) = 1CheckSkip · show solution
