q) if the tangent at P of the curve y2=x3 intersects the curve again at Q and the straight line OP,Oq makes angles A,B with the x-axis ,where O is the origin then (tan A/tanB) =
a)-2 b)-2 c)2 d) 21/2
-
UP 0 DOWN 0 0 2
2 Answers
62let the point be h,k
2y dy/dx = 3x2
dy/dx=3h2/(2k)
equation of the tangent be (y-k)=3h2/(2k)(x-h)
Now substitute the value of y in the original equation y2=x3 to get a cubic in x
Two of these roots are repeated and given by h,h because the point of tangent is a repeated root..
Now using sum of roots find the second point h2 and then k2
Now we have to find (k/h)/(k2/h2)