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If the equation 4x^(3)+5x+k=0(k in R) ha...

If the equation `4x^(3)+5x+k=0(k in R)` has a negative real root then

A

k=0

B

`-ooltklt0`

C

`0ltkltoo`

D

`-ooltkltoo`

Text Solution

Verified by Experts

The correct Answer is:
3
Let (x) =`4x^(3)+5x+k`
`therefore f(x)=12x^(2)+5gt0 for all x in R`
`therefore` f(X) is stictly increasing on R ltrbgt For negative root of the equation f(X) =0 graph of y =f(x) must intersect y axis at positive side
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CENGAGE-MONOTONICITY AND MAXIMA MINIMA OF FUNCTIONS-Exercise (Single)
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