6*f(x)=x3+bx2+cx+d
If f(x)=x3+bx2+cx+d and 0<b2<c, then in (-∞,∞) ,f(x)
(a)is increasing.
(b)is decreasing.
(c)has local maxima.
(d)is bounded.
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2 Answers
11Its derivative is 3x2+2bx+c
now we have to check that it is >0,<0 ,none
as u said earlier 2b>0 and c>2b
so it is clear that f'(x)>0
hence increasing
so (a)