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$$\frac{6 \operatorname{sign}{\left(x \right)}}{\left(\left|{x}\right| - 4\right)^{2}} - \frac{10}{\left(4 x - 12\right)^{\frac{3}{2}}} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}} + \frac{244}{25} + \sqrt{- 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + \frac{9352368}{15625 \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}}} + \frac{55872}{625}}$$
$$x_{2} = - \sqrt{- 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + \frac{9352368}{15625 \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}}} + \frac{55872}{625}} + \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}} + \frac{244}{25}$$
Signos de extremos en los puntos:
______________________________________________________________ _______________________________________________________________________________________________________________________________________________
/ _________________ / _________________
/ / ____ / / ____
244 / 27936 / 324 84*\/ 21 24 / 55872 / 324 84*\/ 21 24 9352368 6 5
(--- + / ----- + 2*3 / --- + --------- - ------------------------- + / ----- - 2*3 / --- + --------- + ------------------------- + ------------------------------------------------------------------------------, - ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- + ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------)
25 / 625 \/ 625 625 _________________ / 625 \/ 625 625 _________________ ______________________________________________________________ ______________________________________________________________ _______________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
/ / ____ / / ____ / _________________ / _________________ / _________________ / ______________________________________________________________ _______________________________________________________________________________________________________________________________________________
/ / 324 84*\/ 21 / / 324 84*\/ 21 / / ____ / / ____ / / ____ / / _________________ / _________________
/ 25*3 / --- + --------- / 25*3 / --- + --------- / 27936 / 324 84*\/ 21 24 144 / 27936 / 324 84*\/ 21 24 / 55872 / 324 84*\/ 21 24 9352368 / / / ____ / / ____
\/ \/ 625 625 / \/ 625 625 15625* / ----- + 2*3 / --- + --------- - ------------------------- --- + / ----- + 2*3 / --- + --------- - ------------------------- + / ----- - 2*3 / --- + --------- + ------------------------- + ------------------------------------------------------------------------------ / 676 / 27936 / 324 84*\/ 21 24 / 55872 / 324 84*\/ 21 24 9352368
/ / 625 \/ 625 625 _________________ 25 / 625 \/ 625 625 _________________ / 625 \/ 625 625 _________________ ______________________________________________________________ / --- + 4* / ----- + 2*3 / --- + --------- - ------------------------- + 4* / ----- - 2*3 / --- + --------- + ------------------------- + ------------------------------------------------------------------------------
/ / / ____ / / ____ / / ____ / _________________ / 25 / 625 \/ 625 625 _________________ / 625 \/ 625 625 _________________ ______________________________________________________________
/ / / 324 84*\/ 21 / / 324 84*\/ 21 / / 324 84*\/ 21 / / ____ / / / ____ / / ____ / _________________
/ / 25*3 / --- + --------- / 25*3 / --- + --------- / 25*3 / --- + --------- / 27936 / 324 84*\/ 21 24 / / / 324 84*\/ 21 / / 324 84*\/ 21 / / ____
\/ \/ \/ 625 625 \/ \/ 625 625 / \/ 625 625 15625* / ----- + 2*3 / --- + --------- - ------------------------- / / 25*3 / --- + --------- / 25*3 / --- + --------- / 27936 / 324 84*\/ 21 24
/ / 625 \/ 625 625 _________________ / \/ \/ 625 625 / \/ 625 625 15625* / ----- + 2*3 / --- + --------- - -------------------------
/ / / ____ / / / 625 \/ 625 625 _________________
/ / / 324 84*\/ 21 / / / / ____
/ / 25*3 / --- + --------- / / / / 324 84*\/ 21
\/ \/ \/ 625 625 / / / 25*3 / --- + ---------
\/ \/ \/ \/ 625 625
______________________________________________________________ _______________________________________________________________________________________________________________________________________________
/ _________________ / _________________
/ / ____ / / ____
244 / 27936 / 324 84*\/ 21 24 / 55872 / 324 84*\/ 21 24 9352368 6 5
(--- + / ----- + 2*3 / --- + --------- - ------------------------- - / ----- - 2*3 / --- + --------- + ------------------------- + ------------------------------------------------------------------------------, - ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- + ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------)
25 / 625 \/ 625 625 _________________ / 625 \/ 625 625 _________________ ______________________________________________________________ ______________________________________________________________ _______________________________________________________________________________________________________________________________________________ _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________
/ / ____ / / ____ / _________________ / _________________ / _________________ / _______________________________________________________________________________________________________________________________________________ ______________________________________________________________
/ / 324 84*\/ 21 / / 324 84*\/ 21 / / ____ / / ____ / / ____ / / _________________ / _________________
/ 25*3 / --- + --------- / 25*3 / --- + --------- / 27936 / 324 84*\/ 21 24 144 / 27936 / 324 84*\/ 21 24 / 55872 / 324 84*\/ 21 24 9352368 / / / ____ / / ____
\/ \/ 625 625 / \/ 625 625 15625* / ----- + 2*3 / --- + --------- - ------------------------- --- + / ----- + 2*3 / --- + --------- - ------------------------- - / ----- - 2*3 / --- + --------- + ------------------------- + ------------------------------------------------------------------------------ / 676 / 55872 / 324 84*\/ 21 24 9352368 / 27936 / 324 84*\/ 21 24
/ / 625 \/ 625 625 _________________ 25 / 625 \/ 625 625 _________________ / 625 \/ 625 625 _________________ ______________________________________________________________ / --- - 4* / ----- - 2*3 / --- + --------- + ------------------------- + ------------------------------------------------------------------------------ + 4* / ----- + 2*3 / --- + --------- - -------------------------
/ / / ____ / / ____ / / ____ / _________________ / 25 / 625 \/ 625 625 _________________ ______________________________________________________________ / 625 \/ 625 625 _________________
/ / / 324 84*\/ 21 / / 324 84*\/ 21 / / 324 84*\/ 21 / / ____ / / / ____ / _________________ / / ____
/ / 25*3 / --- + --------- / 25*3 / --- + --------- / 25*3 / --- + --------- / 27936 / 324 84*\/ 21 24 / / / 324 84*\/ 21 / / ____ / / 324 84*\/ 21
\/ \/ \/ 625 625 \/ \/ 625 625 / \/ 625 625 15625* / ----- + 2*3 / --- + --------- - ------------------------- / / 25*3 / --- + --------- / 27936 / 324 84*\/ 21 24 / 25*3 / --- + ---------
/ / 625 \/ 625 625 _________________ / / \/ 625 625 15625* / ----- + 2*3 / --- + --------- - ------------------------- \/ \/ 625 625
/ / / ____ / / / 625 \/ 625 625 _________________
/ / / 324 84*\/ 21 / / / / ____
/ / 25*3 / --- + --------- / / / / 324 84*\/ 21
\/ \/ \/ 625 625 / / / 25*3 / --- + ---------
\/ \/ \/ \/ 625 625
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:
$$x_{1} = - \sqrt{- 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + \frac{9352368}{15625 \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}}} + \frac{55872}{625}} + \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}} + \frac{244}{25}$$
Puntos máximos de la función:
$$x_{1} = \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}} + \frac{244}{25} + \sqrt{- 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + \frac{9352368}{15625 \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}}} + \frac{55872}{625}}$$
Decrece en los intervalos
$$\left[- \sqrt{- 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + \frac{9352368}{15625 \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}}} + \frac{55872}{625}} + \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}} + \frac{244}{25}, \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}} + \frac{244}{25} + \sqrt{- 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + \frac{9352368}{15625 \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}}} + \frac{55872}{625}}\right]$$
Crece en los intervalos
$$\left(-\infty, - \sqrt{- 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + \frac{9352368}{15625 \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}}} + \frac{55872}{625}} + \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}} + \frac{244}{25}\right] \cup \left[\sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}} + \frac{244}{25} + \sqrt{- 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + \frac{9352368}{15625 \sqrt{- \frac{24}{25 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}}} + 2 \sqrt[3]{\frac{324}{625} + \frac{84 \sqrt{21}}{625}} + \frac{27936}{625}}} + \frac{55872}{625}}, \infty\right)$$