SOLUTION: Explain why 3x^2+kx-1 is never {{{cross(positive)}}} {{{cross(definite)}}} <U>POSITIVELY DEFINED</U> for any value of k.

Algebra ->  Linear-equations -> SOLUTION: Explain why 3x^2+kx-1 is never {{{cross(positive)}}} {{{cross(definite)}}} <U>POSITIVELY DEFINED</U> for any value of k.       Log On


   

Question 1185909: Explain why 3x^2+kx-1 is never cross%28positive%29 cross%28definite%29 POSITIVELY DEFINED for any value of k.
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39617) About Me  (Show Source):
Answer by ikleyn(52781) About Me  (Show Source):
You can put this solution on YOUR website!
.

Consider the value of the given function at   x= 0:   it is  -1,  which is not positive.

It is true for any value of   " k ",   and it shows and proves that the given function
is never positively defined for any value of  " k ".

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Proved and explained.