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$$- \frac{2 \frac{3}{x^{2}}}{x} + 2 x - 2 = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = \frac{\sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}{2} + \frac{1}{4} + \frac{\sqrt{- 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}} + \frac{1}{2} + \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4 \sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}}}{2}$$
$$x_{2} = - \frac{\sqrt{- 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}} + \frac{1}{2} + \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4 \sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}}}{2} + \frac{\sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}{2} + \frac{1}{4}$$
Signos de extremos en los puntos:
2
_________________________________________________________________________________________________________________________ / _________________________________________________________________________________________________________________________\
/ ________________ | / ________________ |
/ / _____ | / / _____ |
/ 1 / 3 \/ 265 2 1 | / 1 / 3 \/ 265 2 1 |
/ - - 2*3 / - -- + ------- + --------------------- + ----------------------------------------------------------------- | / - - 2*3 / - -- + ------- + --------------------- + ----------------------------------------------------------------- |
_____________________________________________________ / 2 \/ 16 16 ________________ _____________________________________________________ | _____________________________________________________ / 2 \/ 16 16 ________________ _____________________________________________________ |
/ ________________ / / _____ / ________________ | / ________________ / / _____ / ________________ |
/ / _____ / / 3 \/ 265 / / _____ | / / _____ / / 3 \/ 265 / / _____ |
/ 1 2 / 3 \/ 265 / 3 / - -- + ------- / 1 2 / 3 \/ 265 | / 1 2 / 3 \/ 265 / 3 / - -- + ------- / 1 2 / 3 \/ 265 |
/ - - --------------------- + 2*3 / - -- + ------- / \/ 16 16 4* / - - --------------------- + 2*3 / - -- + ------- | / - - --------------------- + 2*3 / - -- + ------- / \/ 16 16 4* / - - --------------------- + 2*3 / - -- + ------- |
/ 4 ________________ \/ 16 16 / / 4 ________________ \/ 16 16 | / 4 ________________ \/ 16 16 / / 4 ________________ \/ 16 16 |
/ / _____ / / / _____ | / / _____ / / / _____ | _____________________________________________________ _________________________________________________________________________________________________________________________
/ / 3 \/ 265 / / / 3 \/ 265 | / / 3 \/ 265 / / / 3 \/ 265 | / ________________ / ________________
/ 3 / - -- + ------- / / 3 / - -- + ------- | / 3 / - -- + ------- / / 3 / - -- + ------- | / / _____ / / _____
1 \/ \/ 16 16 \/ \/ \/ 16 16 1 |1 \/ \/ 16 16 \/ \/ \/ 16 16 | / 1 2 / 3 \/ 265 / 1 / 3 \/ 265 2 1 3
(- + --------------------------------------------------------------- + ----------------------------------------------------------------------------------------------------------------------------------------, - - + |- + --------------------------------------------------------------- + ----------------------------------------------------------------------------------------------------------------------------------------| - / - - --------------------- + 2*3 / - -- + ------- - / - - 2*3 / - -- + ------- + --------------------- + ----------------------------------------------------------------- + -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------)
4 2 2 2 \4 2 2 / / 4 ________________ \/ 16 16 / 2 \/ 16 16 ________________ _____________________________________________________ 2
/ / _____ / / _____ / ________________ / _________________________________________________________________________________________________________________________\
/ / 3 \/ 265 / / 3 \/ 265 / / _____ | / ________________ |
/ 3 / - -- + ------- / 3 / - -- + ------- / 1 2 / 3 \/ 265 | / / _____ |
\/ \/ 16 16 / \/ 16 16 4* / - - --------------------- + 2*3 / - -- + ------- | / 1 / 3 \/ 265 2 1 |
/ / 4 ________________ \/ 16 16 | / - - 2*3 / - -- + ------- + --------------------- + ----------------------------------------------------------------- |
/ / / _____ | _____________________________________________________ / 2 \/ 16 16 ________________ _____________________________________________________ |
/ / / 3 \/ 265 | / ________________ / / _____ / ________________ |
/ / 3 / - -- + ------- | / / _____ / / 3 \/ 265 / / _____ |
\/ \/ \/ 16 16 | / 1 2 / 3 \/ 265 / 3 / - -- + ------- / 1 2 / 3 \/ 265 |
| / - - --------------------- + 2*3 / - -- + ------- / \/ 16 16 4* / - - --------------------- + 2*3 / - -- + ------- |
| / 4 ________________ \/ 16 16 / / 4 ________________ \/ 16 16 |
| / / _____ / / / _____ |
| / / 3 \/ 265 / / / 3 \/ 265 |
| / 3 / - -- + ------- / / 3 / - -- + ------- |
|1 \/ \/ 16 16 \/ \/ \/ 16 16 |
|- + --------------------------------------------------------------- + ----------------------------------------------------------------------------------------------------------------------------------------|
\4 2 2 /
2
_________________________________________________________________________________________________________________________ / _________________________________________________________________________________________________________________________\
/ ________________ | / ________________ |
/ / _____ | / / _____ |
/ 1 / 3 \/ 265 2 1 | / 1 / 3 \/ 265 2 1 |
/ - - 2*3 / - -- + ------- + --------------------- + ----------------------------------------------------------------- | / - - 2*3 / - -- + ------- + --------------------- + ----------------------------------------------------------------- |
_____________________________________________________ / 2 \/ 16 16 ________________ _____________________________________________________ | _____________________________________________________ / 2 \/ 16 16 ________________ _____________________________________________________ |
/ ________________ / / _____ / ________________ | / ________________ / / _____ / ________________ |
/ / _____ / / 3 \/ 265 / / _____ | / / _____ / / 3 \/ 265 / / _____ |
/ 1 2 / 3 \/ 265 / 3 / - -- + ------- / 1 2 / 3 \/ 265 | / 1 2 / 3 \/ 265 / 3 / - -- + ------- / 1 2 / 3 \/ 265 |
/ - - --------------------- + 2*3 / - -- + ------- / \/ 16 16 4* / - - --------------------- + 2*3 / - -- + ------- | / - - --------------------- + 2*3 / - -- + ------- / \/ 16 16 4* / - - --------------------- + 2*3 / - -- + ------- |
/ 4 ________________ \/ 16 16 / / 4 ________________ \/ 16 16 | / 4 ________________ \/ 16 16 / / 4 ________________ \/ 16 16 |
/ / _____ / / / _____ | / / _____ / / / _____ | _________________________________________________________________________________________________________________________ _____________________________________________________
/ / 3 \/ 265 / / / 3 \/ 265 | / / 3 \/ 265 / / / 3 \/ 265 | / ________________ / ________________
/ 3 / - -- + ------- / / 3 / - -- + ------- | / 3 / - -- + ------- / / 3 / - -- + ------- | / / _____ / / _____
1 \/ \/ 16 16 \/ \/ \/ 16 16 1 |1 \/ \/ 16 16 \/ \/ \/ 16 16 | / 1 / 3 \/ 265 2 1 / 1 2 / 3 \/ 265 3
(- + --------------------------------------------------------------- - ----------------------------------------------------------------------------------------------------------------------------------------, - - + |- + --------------------------------------------------------------- - ----------------------------------------------------------------------------------------------------------------------------------------| + / - - 2*3 / - -- + ------- + --------------------- + ----------------------------------------------------------------- - / - - --------------------- + 2*3 / - -- + ------- + -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------)
4 2 2 2 \4 2 2 / / 2 \/ 16 16 ________________ _____________________________________________________ / 4 ________________ \/ 16 16 2
/ / _____ / ________________ / / _____ / _________________________________________________________________________________________________________________________\
/ / 3 \/ 265 / / _____ / / 3 \/ 265 | / ________________ |
/ 3 / - -- + ------- / 1 2 / 3 \/ 265 / 3 / - -- + ------- | / / _____ |
/ \/ 16 16 4* / - - --------------------- + 2*3 / - -- + ------- \/ \/ 16 16 | / 1 / 3 \/ 265 2 1 |
/ / 4 ________________ \/ 16 16 | / - - 2*3 / - -- + ------- + --------------------- + ----------------------------------------------------------------- |
/ / / _____ | _____________________________________________________ / 2 \/ 16 16 ________________ _____________________________________________________ |
/ / / 3 \/ 265 | / ________________ / / _____ / ________________ |
/ / 3 / - -- + ------- | / / _____ / / 3 \/ 265 / / _____ |
\/ \/ \/ 16 16 | / 1 2 / 3 \/ 265 / 3 / - -- + ------- / 1 2 / 3 \/ 265 |
| / - - --------------------- + 2*3 / - -- + ------- / \/ 16 16 4* / - - --------------------- + 2*3 / - -- + ------- |
| / 4 ________________ \/ 16 16 / / 4 ________________ \/ 16 16 |
| / / _____ / / / _____ |
| / / 3 \/ 265 / / / 3 \/ 265 |
| / 3 / - -- + ------- / / 3 / - -- + ------- |
|1 \/ \/ 16 16 \/ \/ \/ 16 16 |
|- + --------------------------------------------------------------- - ----------------------------------------------------------------------------------------------------------------------------------------|
\4 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:
$$x_{1} = \frac{\sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}{2} + \frac{1}{4} + \frac{\sqrt{\left|{- 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}} + \frac{1}{2} + \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4 \sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}}\right|}}{2}$$
$$x_{2} = - \frac{\sqrt{\left|{- 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}} + \frac{1}{2} + \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4 \sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}}\right|}}{2} + \frac{\sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}{2} + \frac{1}{4}$$
La función no tiene puntos máximos
Decrece en los intervalos
$$\left[\frac{\sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}{2} + \frac{1}{4} + \frac{\sqrt{\left|{- 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}} + \frac{1}{2} + \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4 \sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}}\right|}}{2}, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, - \frac{\sqrt{\left|{- 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}} + \frac{1}{2} + \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4 \sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}}\right|}}{2} + \frac{\sqrt{- \frac{2}{\sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}} + \frac{1}{4} + 2 \sqrt[3]{- \frac{3}{16} + \frac{\sqrt{265}}{16}}}}{2} + \frac{1}{4}\right]$$