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The equation of the curve in which the portion of the tangent included between the coordinate axes is bisected at the point of contact, isA. a parabolaB. an ellipseC. a circleD. a hyperbola |
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Answer» Correct Answer - D The eqaution of the tangent at any point `P(x,y)` is `Y-y=(dy)/(dx)(X-x)` This cuts the coordinate axes at `A(x-y(dx)/(dy),0) and B(0,y-x(dy)/(dx))`. It is given that `P(x,y)` is the mid-point of AB. `therefore" "x-y(dx)/(dy)=2xand y -x(dy)/(dx)=2y` `rArr" "x+y(dx)/(dy)=0 and y+x(dy)/(dx)=0` `rArr" "x dy+ydx=0 and ydx+xdy =0` `rArr" "d(xy)=0 rArr xy=C` Clearly, it represents a rectangular hyperbola. |
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