1koi to reply karo na
For what value of k does the function
y= x3- 3(7-k)x2-3(9-k2)x+2 , x>0 has a point of maximum ?
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11 Answers
1btw ..your answer does not match with that given in the book
the answer given is k<-3 or 3<k≤ 29/7
3x2 -2(7-k)-(9-k2) = f'(x)
for 1 or more soln.
make D >=0
we get 29/7>=k ............
now to make sure its maxima .... f''(x)<0 ... which it is at the first soln as its a concave upward parabola [f'(x)]......
now we need to make sure first soln is after 0 ........
so at x=0 f'(x) > 0 ......
we get .. either k>3 or k<-3 .............
and f''(0) < 0
or 7>k ,,,,,
but 29/9 is not included else the point where f'(x) =0 .. f''(x) also will be zero :((
takin intersection of all solutions
29/7>k>3
3forgot abt the second part ... sry ... and pls adopt healthy communication ..........
3no.....its not abt that ....... i got irritated by the statement ..
""arey bhai ...solution do ....answer to mere paas bhi hai""
datz all..
1i really didn't mean to hurt you ...it wasn't said as you took it ....
i apologise.