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$$3 \cdot 2^{3 x + 1} \log{\left(2 \right)} - 3^{x} \log{\left(3 \right)} - 3 \cdot 6^{3 x - 1} \log{\left(6 \right)} = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = -64.9855570613729$$
$$x_{2} = -100.985557061373$$
$$x_{3} = -38.9855570794908$$
$$x_{4} = -98.9855570613729$$
$$x_{5} = -108.985557061373$$
$$x_{6} = -58.9855570613729$$
$$x_{7} = -92.9855570613729$$
$$x_{8} = -104.985557061373$$
$$x_{9} = -50.985557061373$$
$$x_{10} = -70.9855570613729$$
$$x_{11} = -68.9855570613729$$
$$x_{12} = -86.9855570613729$$
$$x_{13} = 0.406588491722199$$
$$x_{14} = -54.9855570613729$$
$$x_{15} = -42.9855570617312$$
$$x_{16} = -44.9855570614233$$
$$x_{17} = -60.9855570613729$$
$$x_{18} = -36.9855571902116$$
$$x_{19} = -114.985557061373$$
$$x_{20} = -74.9855570613729$$
$$x_{21} = -1.35468731928638$$
$$x_{22} = -52.9855570613729$$
$$x_{23} = -76.9855570613729$$
$$x_{24} = -66.9855570613729$$
$$x_{25} = -48.9855570613739$$
$$x_{26} = -28.98588658966$$
$$x_{27} = -34.9855579775599$$
$$x_{28} = -82.9855570613729$$
$$x_{29} = -96.9855570613729$$
$$x_{30} = -40.9855570639207$$
$$x_{31} = -110.985557061373$$
$$x_{32} = -26.987903561424$$
$$x_{33} = -118.985557061373$$
$$x_{34} = -30.9856033924444$$
$$x_{35} = -94.9855570613729$$
$$x_{36} = -32.985563576505$$
$$x_{37} = -84.9855570613729$$
$$x_{38} = -80.9855570613729$$
$$x_{39} = -78.9855570613729$$
$$x_{40} = -62.9855570613729$$
$$x_{41} = -116.985557061373$$
$$x_{42} = -90.9855570613729$$
$$x_{43} = -88.9855570613729$$
$$x_{44} = -106.985557061373$$
$$x_{45} = -102.985557061373$$
$$x_{46} = -72.9855570613729$$
$$x_{47} = -112.985557061373$$
$$x_{48} = -56.9855570613729$$
$$x_{49} = -46.98555706138$$
Signos de extremos en los puntos:
(-64.98555706137287, -9.86301006293521e-32)
(-100.98555706137287, -6.57119426248568e-49)
(-38.98555707949082, -2.50704477444229e-19)
(-98.98555706137287, -5.91407483623711e-48)
(-108.98555706137287, -1.00155376657303e-52)
(-58.98555706137287, -7.19013433587977e-29)
(-92.98555706137287, -4.31136055561685e-45)
(-104.98555706137287, -8.11258550924158e-51)
(-50.985557061373015, -4.71744713776998e-25)
(-70.98555706137287, -1.35295062591704e-34)
(-68.98555706137287, -1.21765556332533e-33)
(-86.98555706137287, -3.14298184504469e-42)
(0.4065884917221987, 1.61250327852661)
(-54.98555706137288, -5.82400881206257e-27)
(-42.985557061731164, -3.09511706587306e-21)
(-44.98555706142326, -3.43901896324449e-22)
(-60.98555706137287, -7.98903815097752e-30)
(-36.9855571902116, -2.25634002253862e-18)
(-114.98555706137287, -1.37387347952405e-55)
(-74.98555706137287, -1.67030941471239e-36)
(-1.3546873192863802, -0.106305273005093)
(-52.985557061372894, -5.24160793085623e-26)
(-76.98555706137287, -1.85589934968044e-37)
(-66.98555706137287, -1.0958900069928e-32)
(-48.985557061373875, -4.24570242398897e-24)
(-28.98588658966001, -1.47984906071999e-14)
(-34.98555797755987, -2.03070426374413e-17)
(-82.98555706137287, -2.5458152944862e-40)
(-96.98555706137287, -5.3226673526134e-47)
(-40.98555706392071, -2.78560535258509e-20)
(-110.98555706137287, -1.11283751841448e-53)
(-26.987903561423952, -1.32891618422772e-13)
(-118.98555706137287, -1.69614009817784e-57)
(-30.98560339244445, -1.64478838758211e-15)
(-94.98555706137287, -4.79040061735206e-46)
(-32.98556357650499, -1.82762259550076e-16)
(-84.98555706137287, -2.82868366054022e-41)
(-80.98555706137287, -2.29123376503758e-39)
(-78.98555706137287, -2.06211038853382e-38)
(-62.98555706137287, -8.87670905664169e-31)
(-116.98555706137287, -1.52652608836006e-56)
(-90.98555706137287, -3.88022450005517e-44)
(-88.98555706137287, -3.49220205004965e-43)
(-106.98555706137287, -9.01398389915731e-52)
(-102.98555706137287, -7.30132695831742e-50)
(-72.98555706137287, -1.50327847324115e-35)
(-112.98555706137287, -1.23648613157165e-54)
(-56.98555706137287, -6.47112090229179e-28)
(-46.98555706137996, -3.82113218156454e-23)
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:
$$x_{1} = -1.35468731928638$$
Puntos máximos de la función:
$$x_{1} = 0.406588491722199$$
Decrece en los intervalos
$$\left[-1.35468731928638, 0.406588491722199\right]$$
Crece en los intervalos
$$\left(-\infty, -1.35468731928638\right] \cup \left[0.406588491722199, \infty\right)$$