Para hallar los extremos hay que resolver la ecuación
$$\frac{d}{d x} f{\left(x \right)} = 0$$
(la derivada es igual a cero),
y las raíces de esta ecuación serán los extremos de esta función:
$$\frac{d}{d x} f{\left(x \right)} = $$
primera derivada$$5 x^{4} - 4 x^{3} + 2 x - 1 = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = - \frac{\sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}{2} + \frac{1}{5} + \frac{\sqrt{- 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}} + \frac{8}{25} + \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{84}{125 \sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}}}{2}$$
$$x_{2} = - \frac{\sqrt{- 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}} + \frac{8}{25} + \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{84}{125 \sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}}}{2} - \frac{\sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}{2} + \frac{1}{5}$$
Signos de extremos en los puntos:
2 5 4
___________________________________________________________________________________________________________________________ / ___________________________________________________________________________________________________________________________ \ / ___________________________________________________________________________________________________________________________ \ / ___________________________________________________________________________________________________________________________ \ ___________________________________________________________________________________________________________________________
/ ______________ | / ______________ | | / ______________ | | / ______________ | / ______________
/ / ____ | / / ____ | | / / ____ | | / / ____ | / / ____
/ 8 / 1 \/ 17 2 84 | / 8 / 1 \/ 17 2 84 | | / 8 / 1 \/ 17 2 84 | | / 8 / 1 \/ 17 2 84 | / 8 / 1 \/ 17 2 84
/ -- - 2*3 / --- + ------ + ---------------------- + ------------------------------------------------------------------- | / -- - 2*3 / --- + ------ + ---------------------- + ------------------------------------------------------------------- | | / -- - 2*3 / --- + ------ + ---------------------- + ------------------------------------------------------------------- | | / -- - 2*3 / --- + ------ + ---------------------- + ------------------------------------------------------------------- | / -- - 2*3 / --- + ------ + ---------------------- + -------------------------------------------------------------------
/ 25 \/ 500 500 ______________ _____________________________________________________ _____________________________________________________ | / 25 \/ 500 500 ______________ _____________________________________________________ _____________________________________________________| | / 25 \/ 500 500 ______________ _____________________________________________________ _____________________________________________________| _____________________________________________________ | / 25 \/ 500 500 ______________ _____________________________________________________ _____________________________________________________| / 25 \/ 500 500 ______________ _____________________________________________________
/ / ____ / ______________ / ______________ | / / ____ / ______________ / ______________ | | / / ____ / ______________ / ______________ | / ______________ | / / ____ / ______________ / ______________ | / / ____ / ______________
/ / 1 \/ 17 / / ____ / / ____ | / / 1 \/ 17 / / ____ / / ____ | | / / 1 \/ 17 / / ____ / / ____ | / / ____ | / / 1 \/ 17 / / ____ / / ____ | / / 1 \/ 17 / / ____
/ 25*3 / --- + ------ / 4 / 1 \/ 17 2 / 4 / 1 \/ 17 2 | / 25*3 / --- + ------ / 4 / 1 \/ 17 2 / 4 / 1 \/ 17 2 | | / 25*3 / --- + ------ / 4 / 1 \/ 17 2 / 4 / 1 \/ 17 2 | / 4 / 1 \/ 17 2 | / 25*3 / --- + ------ / 4 / 1 \/ 17 2 / 4 / 1 \/ 17 2 | / 25*3 / --- + ------ / 4 / 1 \/ 17 2
/ \/ 500 500 125* / -- + 2*3 / --- + ------ - ---------------------- / -- + 2*3 / --- + ------ - ---------------------- | / \/ 500 500 125* / -- + 2*3 / --- + ------ - ---------------------- / -- + 2*3 / --- + ------ - ---------------------- | | / \/ 500 500 125* / -- + 2*3 / --- + ------ - ---------------------- / -- + 2*3 / --- + ------ - ---------------------- | / -- + 2*3 / --- + ------ - ---------------------- | / \/ 500 500 125* / -- + 2*3 / --- + ------ - ---------------------- / -- + 2*3 / --- + ------ - ---------------------- | / \/ 500 500 125* / -- + 2*3 / --- + ------ - ----------------------
/ / 25 \/ 500 500 ______________ / 25 \/ 500 500 ______________ | / / 25 \/ 500 500 ______________ / 25 \/ 500 500 ______________ | | / / 25 \/ 500 500 ______________ / 25 \/ 500 500 ______________ | / 25 \/ 500 500 ______________ | / / 25 \/ 500 500 ______________ / 25 \/ 500 500 ______________ | / / 25 \/ 500 500 ______________
/ / / ____ / / ____ | / / / ____ / / ____ | | / / / ____ / / ____ | / / ____ | / / / ____ / / ____ | / / / ____
/ / / 1 \/ 17 / / 1 \/ 17 | / / / 1 \/ 17 / / 1 \/ 17 | | / / / 1 \/ 17 / / 1 \/ 17 | / / 1 \/ 17 | / / / 1 \/ 17 / / 1 \/ 17 | / / / 1 \/ 17
/ / 25*3 / --- + ------ / 25*3 / --- + ------ | / / 25*3 / --- + ------ / 25*3 / --- + ------ | | / / 25*3 / --- + ------ / 25*3 / --- + ------ | / 25*3 / --- + ------ | / / 25*3 / --- + ------ / 25*3 / --- + ------ | / / 25*3 / --- + ------
1 \/ \/ \/ 500 500 \/ \/ 500 500 4 |1 \/ \/ \/ 500 500 \/ \/ 500 500 | |1 \/ \/ \/ 500 500 \/ \/ 500 500 | \/ \/ 500 500 |1 \/ \/ \/ 500 500 \/ \/ 500 500 | \/ \/ \/ 500 500
(- + ------------------------------------------------------------------------------------------------------------------------------------------ - ---------------------------------------------------------------, - + |- + ------------------------------------------------------------------------------------------------------------------------------------------ - ---------------------------------------------------------------| + |- + ------------------------------------------------------------------------------------------------------------------------------------------ - ---------------------------------------------------------------| + --------------------------------------------------------------- - |- + ------------------------------------------------------------------------------------------------------------------------------------------ - ---------------------------------------------------------------| - ------------------------------------------------------------------------------------------------------------------------------------------)
5 2 2 5 \5 2 2 / \5 2 2 / 2 \5 2 2 / 2
2 5 4
___________________________________________________________________________________________________________________________ / ___________________________________________________________________________________________________________________________\ / ___________________________________________________________________________________________________________________________\ ___________________________________________________________________________________________________________________________ / ___________________________________________________________________________________________________________________________\
/ ______________ | / ______________ | | / ______________ | / ______________ | / ______________ |
/ / ____ | / / ____ | | / / ____ | / / ____ | / / ____ |
/ 8 / 1 \/ 17 2 84 | / 8 / 1 \/ 17 2 84 | | / 8 / 1 \/ 17 2 84 | / 8 / 1 \/ 17 2 84 | / 8 / 1 \/ 17 2 84 |
/ -- - 2*3 / --- + ------ + ---------------------- + ------------------------------------------------------------------- | / -- - 2*3 / --- + ------ + ---------------------- + ------------------------------------------------------------------- | | / -- - 2*3 / --- + ------ + ---------------------- + ------------------------------------------------------------------- | / -- - 2*3 / --- + ------ + ---------------------- + ------------------------------------------------------------------- | / -- - 2*3 / --- + ------ + ---------------------- + ------------------------------------------------------------------- |
_____________________________________________________ / 25 \/ 500 500 ______________ _____________________________________________________ | _____________________________________________________ / 25 \/ 500 500 ______________ _____________________________________________________ | | _____________________________________________________ / 25 \/ 500 500 ______________ _____________________________________________________ | _____________________________________________________ / 25 \/ 500 500 ______________ _____________________________________________________ | _____________________________________________________ / 25 \/ 500 500 ______________ _____________________________________________________ |
/ ______________ / / ____ / ______________ | / ______________ / / ____ / ______________ | | / ______________ / / ____ / ______________ | / ______________ / / ____ / ______________ | / ______________ / / ____ / ______________ |
/ / ____ / / 1 \/ 17 / / ____ | / / ____ / / 1 \/ 17 / / ____ | | / / ____ / / 1 \/ 17 / / ____ | / / ____ / / 1 \/ 17 / / ____ | / / ____ / / 1 \/ 17 / / ____ |
/ 4 / 1 \/ 17 2 / 25*3 / --- + ------ / 4 / 1 \/ 17 2 | / 4 / 1 \/ 17 2 / 25*3 / --- + ------ / 4 / 1 \/ 17 2 | | / 4 / 1 \/ 17 2 / 25*3 / --- + ------ / 4 / 1 \/ 17 2 | / 4 / 1 \/ 17 2 / 25*3 / --- + ------ / 4 / 1 \/ 17 2 | / 4 / 1 \/ 17 2 / 25*3 / --- + ------ / 4 / 1 \/ 17 2 |
/ -- + 2*3 / --- + ------ - ---------------------- / \/ 500 500 125* / -- + 2*3 / --- + ------ - ---------------------- | / -- + 2*3 / --- + ------ - ---------------------- / \/ 500 500 125* / -- + 2*3 / --- + ------ - ---------------------- | | / -- + 2*3 / --- + ------ - ---------------------- / \/ 500 500 125* / -- + 2*3 / --- + ------ - ---------------------- | / -- + 2*3 / --- + ------ - ---------------------- / \/ 500 500 125* / -- + 2*3 / --- + ------ - ---------------------- | / -- + 2*3 / --- + ------ - ---------------------- / \/ 500 500 125* / -- + 2*3 / --- + ------ - ---------------------- |
/ 25 \/ 500 500 ______________ / / 25 \/ 500 500 ______________ | / 25 \/ 500 500 ______________ / / 25 \/ 500 500 ______________ | | / 25 \/ 500 500 ______________ / / 25 \/ 500 500 ______________ | / 25 \/ 500 500 ______________ / / 25 \/ 500 500 ______________ | / 25 \/ 500 500 ______________ / / 25 \/ 500 500 ______________ |
/ / ____ / / / ____ | / / ____ / / / ____ | | / / ____ / / / ____ | / / ____ / / / ____ | / / ____ / / / ____ |
/ / 1 \/ 17 / / / 1 \/ 17 | / / 1 \/ 17 / / / 1 \/ 17 | | / / 1 \/ 17 / / / 1 \/ 17 | / / 1 \/ 17 / / / 1 \/ 17 | / / 1 \/ 17 / / / 1 \/ 17 |
/ 25*3 / --- + ------ / / 25*3 / --- + ------ | / 25*3 / --- + ------ / / 25*3 / --- + ------ | | / 25*3 / --- + ------ / / 25*3 / --- + ------ | / 25*3 / --- + ------ / / 25*3 / --- + ------ | / 25*3 / --- + ------ / / 25*3 / --- + ------ |
1 \/ \/ 500 500 \/ \/ \/ 500 500 4 |1 \/ \/ 500 500 \/ \/ \/ 500 500 | |1 \/ \/ 500 500 \/ \/ \/ 500 500 | \/ \/ 500 500 \/ \/ \/ 500 500 |1 \/ \/ 500 500 \/ \/ \/ 500 500 |
(- - --------------------------------------------------------------- - ------------------------------------------------------------------------------------------------------------------------------------------, - + |- - --------------------------------------------------------------- - ------------------------------------------------------------------------------------------------------------------------------------------| + |- - --------------------------------------------------------------- - ------------------------------------------------------------------------------------------------------------------------------------------| + --------------------------------------------------------------- + ------------------------------------------------------------------------------------------------------------------------------------------ - |- - --------------------------------------------------------------- - ------------------------------------------------------------------------------------------------------------------------------------------| )
5 2 2 5 \5 2 2 / \5 2 2 / 2 2 \5 2 2 /
Intervalos de crecimiento y decrecimiento de la función:Hallemos los intervalos donde la función crece y decrece y también los puntos mínimos y máximos de la función, para lo cual miramos cómo se comporta la función en los extremos con desviación mínima del extremo:
Puntos mínimos de la función:
$$x_{1} = - \frac{\sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}{2} + \frac{1}{5} + \frac{\sqrt{\left|{- 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}} + \frac{8}{25} + \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{84}{125 \sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}}\right|}}{2}$$
Puntos máximos de la función:
$$x_{1} = - \frac{\sqrt{\left|{- 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}} + \frac{8}{25} + \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{84}{125 \sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}}\right|}}{2} - \frac{\sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}{2} + \frac{1}{5}$$
Decrece en los intervalos
$$\left(-\infty, - \frac{\sqrt{\left|{- 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}} + \frac{8}{25} + \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{84}{125 \sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}}\right|}}{2} - \frac{\sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}{2} + \frac{1}{5}\right] \cup \left[- \frac{\sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}{2} + \frac{1}{5} + \frac{\sqrt{\left|{- 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}} + \frac{8}{25} + \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{84}{125 \sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}}\right|}}{2}, \infty\right)$$
Crece en los intervalos
$$\left[- \frac{\sqrt{\left|{- 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}} + \frac{8}{25} + \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{84}{125 \sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}}\right|}}{2} - \frac{\sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}{2} + \frac{1}{5}, - \frac{\sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}{2} + \frac{1}{5} + \frac{\sqrt{\left|{- 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}} + \frac{8}{25} + \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{84}{125 \sqrt{- \frac{2}{25 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}} + \frac{4}{25} + 2 \sqrt[3]{\frac{1}{500} + \frac{\sqrt{17}}{500}}}}}\right|}}{2}\right]$$