Find the critical numbers of the function.$\displaystyle f(x) = x^3 + x^2 - x$

whats the smaller value and the larger value?

the derivative of this is

3x^2+2x-1 but i get lost right after.

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- Nov 18th 2009, 02:14 PMbreakcritical numbers
Find the critical numbers of the function.$\displaystyle f(x) = x^3 + x^2 - x$

whats the smaller value and the larger value?

the derivative of this is

3x^2+2x-1 but i get lost right after. - Nov 18th 2009, 02:22 PMskeeter
- Nov 18th 2009, 02:30 PMbreak
okay so

$\displaystyle 3x^2+2x-1=0$

$\displaystyle 2x-1=3x^2$

$\displaystyle -1=3x^2/2x$

$\displaystyle -1=3x/2$

$\displaystyle 0 = (3x+2)/2$

then

$\displaystyle 0 = 3x+2$

$\displaystyle -2/3 = x$

not sure if i got this part right. - Nov 18th 2009, 02:41 PMpropjohn
- Nov 18th 2009, 02:42 PMpropjohn
- Nov 18th 2009, 02:53 PMskeeter