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$$\left(\frac{2 x + 3}{5 x + 7}\right)^{x} \left(\frac{x \left(5 x + 7\right) \left(- \frac{5 \left(2 x + 3\right)}{\left(5 x + 7\right)^{2}} + \frac{2}{5 x + 7}\right)}{2 x + 3} + \log{\left(\frac{2 x + 3}{5 x + 7} \right)}\right) = 0$$
Resolvermos esta ecuaciónRaíces de esta ecuación
$$x_{1} = 109.102141534576$$
$$x_{2} = 37.1087290700992$$
$$x_{3} = 85.1024432893594$$
$$x_{4} = 97.1022600864649$$
$$x_{5} = 71.1028197593887$$
$$x_{6} = 77.1026275841769$$
$$x_{7} = 89.1023724224524$$
$$x_{8} = 87.1024064041839$$
$$x_{9} = 79.1025750721714$$
$$x_{10} = 65.1030842857598$$
$$x_{11} = 91.1023410453493$$
$$x_{12} = 49.1046017931833$$
$$x_{13} = 39.1075519741403$$
$$x_{14} = 35.1103393597195$$
$$x_{15} = 119.102071995832$$
$$x_{16} = 47.1049694362563$$
$$x_{17} = 43.1059677107542$$
$$x_{18} = 83.1024834212672$$
$$x_{19} = 111.102125903823$$
$$x_{20} = 107.102158176818$$
$$x_{21} = 75.1026853568851$$
$$x_{22} = 53.1040367710319$$
$$x_{23} = 121.10206035785$$
$$x_{24} = 105.102175920182$$
$$x_{25} = 81.1025271959209$$
$$x_{26} = 61.1033205380394$$
$$x_{27} = 41.1066609534818$$
$$x_{28} = 31.1161683892147$$
$$x_{29} = 113.102111203901$$
$$x_{30} = 103.102194864502$$
$$x_{31} = 69.1028982941325$$
$$x_{32} = 99.1022368152189$$
$$x_{33} = 67.1029859703397$$
$$x_{34} = 45.1054162434891$$
$$x_{35} = 123.102049349476$$
$$x_{36} = 57.1036273661864$$
$$x_{37} = 51.1042952701951$$
$$x_{38} = 95.102285092648$$
$$x_{39} = -1.85149865012209$$
$$x_{40} = 63.1031950627835$$
$$x_{41} = 101.102215121253$$
$$x_{42} = 73.1027491253988$$
$$x_{43} = 59.1034634826815$$
$$x_{44} = 33.1126461424691$$
$$x_{45} = 117.102084312556$$
$$x_{46} = 55.1038165829182$$
$$x_{47} = 93.1023120117544$$
$$x_{48} = 115.102097362062$$
Signos de extremos en los puntos:
(109.10214153457576, 1)
(37.108729070099194, 1)
(85.10244328935941, 1)
(97.10226008646494, 1)
(71.10281975938872, 1)
(77.10262758417689, 1)
(89.10237242245245, 1)
(87.10240640418388, 1)
(79.10257507217143, 1)
(65.10308428575979, 1)
(91.10234104534928, 1)
(49.10460179318331, 1)
(39.10755197414032, 1)
(35.11033935971951, 1.00000000000001)
(119.102071995832, 1)
(47.10496943625628, 1)
(43.105967710754214, 1)
(83.10248342126724, 1)
(111.10212590382288, 1)
(107.1021581768182, 1)
(75.10268535688509, 1)
(53.10403677103191, 1)
(121.10206035784972, 1)
(105.1021759201819, 1)
(81.1025271959209, 1)
(61.10332053803937, 1)
(41.10666095348184, 1)
(31.116168389214693, 1.00000000000046)
(113.10211120390053, 1)
(103.10219486450247, 1)
(69.1028982941325, 1)
(99.1022368152189, 1)
(67.10298597033967, 1)
(45.105416243489145, 1)
(123.10204934947583, 1)
(57.10362736618636, 1)
(51.10429527019514, 1)
(95.10228509264799, 1)
(-1.8514986501220936, 9.6716953391525)
(63.10319506278352, 1)
(101.10221512125284, 1)
(73.10274912539876, 1)
(59.10346348268153, 1)
(33.11264614246911, 1.00000000000007)
(117.1020843125559, 1)
(55.103816582918164, 1)
(93.1023120117544, 1)
(115.10209736206195, 1)
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:
$$x_{1} = -1.85149865012209$$
La función no tiene puntos máximos
Decrece en los intervalos
$$\left[-1.85149865012209, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -1.85149865012209\right]$$