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## Homework Statement

## Homework Equations

Rolle's Theorem:

If f(a)=f(b)=0 then there is at least one a<c<b such that f'(c)=0

## The Attempt at a Solution

$$y=2x^3-3x^2-12x-6~\rightarrow~y'=6x^2-6x-12$$

The function:

y':

How do i know y' isn't 0 somewhere? if it's continuously descending, so i make y''=12x-6. it's a straight line, so there are no twist points in y'.

But to know y'' doesn't equal 0 somewhere i take y'''=12

Do i really need to reach y''' in order to answer the question? i think i exaggerate

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