62
Lokesh Verma
·2008-11-21 06:35:07
no i think there is more to it..
it is given x>0
so u will have to take that the derivative has a +ve root!
1
big looser .........
·2008-11-21 06:49:15
i know the method, i want answer. my answer is not matching with that given in the book
its from a.das
62
Lokesh Verma
·2008-11-21 06:55:56
i am getting (-3,29/7)
to be true.. din do with utmost sincerity .. just rushed to get the answer.. tell me if it is correct or wrong.
and then the right answer and ur answer.. so that we can work more :)
1
big looser .........
·2008-11-21 07:01:49
actual answer (-∞,3) U (3,29/7)
my answer (-∞,3) U (3,7)
1
ith_power
·2008-11-21 07:05:47
first of all derivative:
3x^2-6(7-k)x-3(9-k^2). this equation must have 2(one +ve x for maxima and another +ve x for minima) +ve roots. then,
at x=0, -3(9-k^2)>0,implying k^2>9. also derivative of above equation 6x-6(7-k)=0 must have a +ve root.(at the pt. of minima of the parabola.) so, 7>k.
but, discriminant should be>0, then we get k<29/7