MathematicsEasy74×since 2004Q3750Let S = {(x,y)∈R2:y21+r−x21−r};r≠±1.\left\{ {\left( {x,y} \right) \in {R^2}:{{{y^2}} \over {1 + r}} - {{{x^2}} \over {1 - r}}} \right\};r \ne \pm 1.{(x,y)∈R2:1+ry2−1−rx2};r=±1. Then S represents :Aan ellipse whose eccentricity is 1r+1,{1 \over {\sqrt {r + 1} }},r+11, where r > 1Ban ellipse whose eccentricity is 2r+1,{2 \over {\sqrt {r + 1} }},r+12, where 0 < r < 1Can ellipse whose eccentricity is 2r−1,{2 \over {\sqrt {r - 1} }},r−12, where 0 < r < 1Dan ellipse whose eccentricity is 2r+1\sqrt {{2 \over {r + 1}}}r+12, where r > 1Check answerSkip