MathematicsMedium63×since 2002Q3675If y=sec(tan−1x),y = \sec \left( {{{\tan }^{ - 1}}x} \right),y=sec(tan−1x), then dydx{{{dy} \over {dx}}}dxdy at x=1x=1x=1 is equal to :A12{1 \over {\sqrt 2 }}21B12{1 \over 2}21C111D2\sqrt 22Check answerSkip