Find the critical numbers of the function. (Enter your answers as a comma-separated list. If an answer does not exist, enter DNE.) f(x) = 2x3 − 3x2 − 36x

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Answer:

The critical points of [tex]f(x) = 2\cdot x^{3}-3\cdot x^{2}-36\cdot x[/tex] are [tex]x_{1} = 3[/tex] and [tex]x_{2} = -2[/tex]. {-2, 3}

Step-by-step explanation:

We must use First Derivative Test to determine all critical numbers of the function [tex]f(x) = 2\cdot x^{3}-3\cdot x^{2}-36\cdot x[/tex]

As first step we need its first and second derivatives:

First derivative

[tex]f'(x) = 6\cdot x^{2}-6\cdot x-36[/tex] (Eq. 1)

Now, we equalize (Eq. 1) to find all critical numbers and solve it afterwards:

[tex]6\cdot x^{2}-6\cdot x-36 = 0[/tex]

By Quadratic Formula all roots are found:

[tex]x_{1} = 3[/tex] and [tex]x_{2} = -2[/tex]

The critical points of [tex]f(x) = 2\cdot x^{3}-3\cdot x^{2}-36\cdot x[/tex] are [tex]x_{1} = 3[/tex] and [tex]x_{2} = -2[/tex]. {-2, 3}

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