Se da la desigualdad:
3x−4log(53x−1)(∣x∣−2)<0Para resolver esta desigualdad primero hay que resolver la ecuación correspondiente:
3x−4log(53x−1)(∣x∣−2)=0Resolvemos:
x1=2x2=99.5489461011519x3=93.569076935984x4=−1.58824836707847+1.21551105485412ix5=69.6955656021939x6=89.5843484961848x7=47.986138217215x8=53.8721104571523x9=34.5865198984739x10=38.3274738944155x11=101.542871331041x12=0.239810685711167−1.98557065727179ix13=117.502985828178x14=44.0911138123982x15=77.6422682789124x16=46.0348974386323x17=111.516357806476x18=75.6542283996978x19=107.526259258136x20=−1.99183624728629+0.180522475045236ix21=91.5765077934754x22=63.7475479215625x23=113.511715370856x24=61.7679847128898x25=81.6205699126418x26=103.537077665171x27=79.6310724235353x28=57.8149061867567x29=−1.90471137738747+0.609979154439506ix30=40.2342227391959x31=−1.66293534725546+1.11114626888109ix32=73.6670337421039x33=31.0371486419629x34=115.507261797432x35=29.4315516048316x36=−1.91639660213643+0.572209807081247ix37=−1.86464911627047−0.723245237241096ix38=95.5620246791833x39=97.5553228758457x40=71.6807771448587x41=67.7115230823567x42=59.7903423536149x43=85.6014026112032x44=105.531546087423x45=32.7757404339411x46=87.5926338246734x47=42.1566825563676x48=49.9434275339244x49=51.9056947463735x50=−2x51=−1.75828888460461+0.953110800629115ix52=83.6106983486007x53=119.498877081524x54=36.4419983188166x55=65.7287940517843x56=55.8420215236371x57=109.521201333264Descartamos las soluciones complejas:
x1=2x2=99.5489461011519x3=93.569076935984x4=69.6955656021939x5=89.5843484961848x6=47.986138217215x7=53.8721104571523x8=34.5865198984739x9=38.3274738944155x10=101.542871331041x11=117.502985828178x12=44.0911138123982x13=77.6422682789124x14=46.0348974386323x15=111.516357806476x16=75.6542283996978x17=107.526259258136x18=91.5765077934754x19=63.7475479215625x20=113.511715370856x21=61.7679847128898x22=81.6205699126418x23=103.537077665171x24=79.6310724235353x25=57.8149061867567x26=40.2342227391959x27=73.6670337421039x28=31.0371486419629x29=115.507261797432x30=29.4315516048316x31=95.5620246791833x32=97.5553228758457x33=71.6807771448587x34=67.7115230823567x35=59.7903423536149x36=85.6014026112032x37=105.531546087423x38=32.7757404339411x39=87.5926338246734x40=42.1566825563676x41=49.9434275339244x42=51.9056947463735x43=−2x44=83.6106983486007x45=119.498877081524x46=36.4419983188166x47=65.7287940517843x48=55.8420215236371x49=109.521201333264Las raíces dadas
x43=−2x1=2x30=29.4315516048316x28=31.0371486419629x38=32.7757404339411x8=34.5865198984739x46=36.4419983188166x9=38.3274738944155x26=40.2342227391959x40=42.1566825563676x12=44.0911138123982x14=46.0348974386323x6=47.986138217215x41=49.9434275339244x42=51.9056947463735x7=53.8721104571523x48=55.8420215236371x25=57.8149061867567x35=59.7903423536149x21=61.7679847128898x19=63.7475479215625x47=65.7287940517843x34=67.7115230823567x4=69.6955656021939x33=71.6807771448587x27=73.6670337421039x16=75.6542283996978x13=77.6422682789124x24=79.6310724235353x22=81.6205699126418x44=83.6106983486007x36=85.6014026112032x39=87.5926338246734x5=89.5843484961848x18=91.5765077934754x3=93.569076935984x31=95.5620246791833x32=97.5553228758457x2=99.5489461011519x10=101.542871331041x23=103.537077665171x37=105.531546087423x17=107.526259258136x49=109.521201333264x15=111.516357806476x20=113.511715370856x29=115.507261797432x11=117.502985828178x45=119.498877081524son puntos de cambio del signo de desigualdad en las soluciones.
Primero definámonos con el signo hasta el punto extremo izquierdo:
x0<x43Consideremos, por ejemplo, el punto
x0=x43−101=
−2+−101=
−2.1lo sustituimos en la expresión
3x−4log(53x−1)(∣x∣−2)<0−4+3−2.1log(5(−2.1)3−1)(−2+∣−2.1∣)<0-0.0209043830784063 - 0.0256380735810831*pi*I < 0
Entonces
x<−2no se cumple
significa que una de las soluciones de nuestra ecuación será con:
x>−2∧x<2 _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____ _____
/ \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ / \ /
-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------ο-------
x43 x1 x30 x28 x38 x8 x46 x9 x26 x40 x12 x14 x6 x41 x42 x7 x48 x25 x35 x21 x19 x47 x34 x4 x33 x27 x16 x13 x24 x22 x44 x36 x39 x5 x18 x3 x31 x32 x2 x10 x23 x37 x17 x49 x15 x20 x29 x11 x45
Recibiremos otras soluciones de la desigualdad pasando al polo siguiente etc.
etc.
Respuesta:
x>−2∧x<2x>29.4315516048316∧x<31.0371486419629x>32.7757404339411∧x<34.5865198984739x>36.4419983188166∧x<38.3274738944155x>40.2342227391959∧x<42.1566825563676x>44.0911138123982∧x<46.0348974386323x>47.986138217215∧x<49.9434275339244x>51.9056947463735∧x<53.8721104571523x>55.8420215236371∧x<57.8149061867567x>59.7903423536149∧x<61.7679847128898x>63.7475479215625∧x<65.7287940517843x>67.7115230823567∧x<69.6955656021939x>71.6807771448587∧x<73.6670337421039x>75.6542283996978∧x<77.6422682789124x>79.6310724235353∧x<81.6205699126418x>83.6106983486007∧x<85.6014026112032x>87.5926338246734∧x<89.5843484961848x>91.5765077934754∧x<93.569076935984x>95.5620246791833∧x<97.5553228758457x>99.5489461011519∧x<101.542871331041x>103.537077665171∧x<105.531546087423x>107.526259258136∧x<109.521201333264x>111.516357806476∧x<113.511715370856x>115.507261797432∧x<117.502985828178x>119.498877081524