A) \[k=0\]
B) \[-\infty <k<0\]
C) \[0<k<\infty \]
D) \[-\infty <k<\infty \]
Correct Answer: C
Solution :
\[f(x)=4{{x}^{3}}+5x+k\] \[f'(x)=12{{x}^{2}}+5>0\forall x\in R\] \[\therefore \]\[f(x)\] is strictly increasing on R. So, for \[f(x)=0\] to have a negative real root, \[f(0)>0\Rightarrow k>0\]You need to login to perform this action.
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