1The answer is 4.
The tangent and normal to the parabola y2=8x drwan at (2,4) intersect the line lx+y=3 at the points A and B respectively.If AB subtends a right angle at the vertex of the parabola then sum of all possible values of l is:
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5 Answers
6write the eqns of tangent and parabola ..........
find the pts of intersecn,
then homogenise with parabola
and then coeff. of (a+b) = 0
11is it so???
bt i m getting the answer as -1.
i simply found out the equns. for the tanget and normal..
simultaneously solved it with the line given... got the co-ordinates of A and B...
found out the slope of AO and BO... where O is the vertex i.e, (0,0)
and equatd their product with -1 (as they are perp.)
i m getting this,
(1-2l)(2l+3)=-1
solving the quadritic i got the sum of the roots as -1. :(
pls check...