mani i am getting XY=(33/8)
Q
17. The locus of the vertices of the family of parabolas y=a^{3}x^{2}/3+ a^{2}x 2a is
(1) xy= 105/64
(2) xy= 3/4
(3) xy= 35/16
(4) xy=64/105

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10 Answers
Lokesh Verma
·20090418 00:36:37
17. The locus of the vertices of the family of parabolas y=a^{3}x^{2}/3+ a^{2}x 2a is
(1) xy= 105/64
(2) xy= 3/4
(3) xy= 35/16
(4) xy=64/105
y=a^{3}x^{2}/3+ a^{2}x 2a
The vertex will be the point where dy/dx = 0 (Think of it as a parabola)
2a^{3}x/3+ a^{2} = 0
so x=3/2a
there, y= ax3/4  ax3/2 2a = 11/4 a
thus, xy=33/8 should be the answer
Mani Pal Singh
·20090418 12:34:29
dude i am not saying that sir and u r wrong
but ur answer is not even in the options
then wat to do?
Dharun
·20090418 12:42:39
i am saying that soln u gvn is wrong
there r some ques like this its very few