Saved Bookmarks
| 1. |
Consider the parabola `y^(2)=8x,` if the normal at a point P on the parabola meets it again at a point Q, then the least distance of Q from the tangent at the vertex of the parabola isA. `16`B. `8`C. `0`D. None of these |
|
Answer» Correct Answer - A `P-=(at_(1)^(2),2at_(1)),Q-=(at_(2)^(2),2at_(2))`, then `t_(2)=-t_(1)-(2)/(t_(1))` Here `4a =8" " therefore a=2` Required distance, `z=at_(2)^(2)=2(t_(1)^(2)+(4)/(t_(1)^(2))+4)=2[(t_(1)-(2)/(t_(1)))^(2)+8...(i)` `implies zge2(8)]...(i)` `therefore "least value of" z=16 ["from" (i)]` |
|