MathematicsMedium63×since 2002Q3671Let y = y(x) be a function of x satisfying y1−x2=k−x1−y2y\sqrt {1 - {x^2}} = k - x\sqrt {1 - {y^2}}y1−x2=k−x1−y2 where k is a constant and y(12)=−14y\left( {{1 \over 2}} \right) = - {1 \over 4}y(21)=−41. Then dydx{{dy} \over {dx}}dxdy at x = 12{1 \over 2}21, is equal to :A25{2 \over {\sqrt 5 }}52B−52- {{\sqrt 5 } \over 2}−25C52{{\sqrt 5 } \over 2}25D−54- {{\sqrt 5 } \over 4}−45Check answerSkip