Sr Examen

Gráfico de la función y = exp(x)/2-cos(x)+sin(x)

v

Gráfico:

interior superior

Puntos de intersección:

mostrar?

Definida a trozos:

Solución

Ha introducido [src]
        x                  
       e                   
f(x) = -- - cos(x) + sin(x)
       2                   
f(x)=(ex2cos(x))+sin(x)f{\left(x \right)} = \left(\frac{e^{x}}{2} - \cos{\left(x \right)}\right) + \sin{\left(x \right)}
f = exp(x)/2 - cos(x) + sin(x)
Gráfico de la función
02468-8-6-4-2-101020000-10000
Puntos de cruce con el eje de coordenadas X
El gráfico de la función cruce el eje X con f = 0
o sea hay que resolver la ecuación:
(ex2cos(x))+sin(x)=0\left(\frac{e^{x}}{2} - \cos{\left(x \right)}\right) + \sin{\left(x \right)} = 0
Resolvermos esta ecuación
Puntos de cruce con el eje X:

Solución numérica
x1=8.63931721569265x_{1} = -8.63931721569265
x2=65.1880475619882x_{2} = -65.1880475619882
x3=0.292130748452471x_{3} = 0.292130748452471
x4=0.292130748452456x_{4} = 0.292130748452456
x5=14.9225649876911x_{5} = -14.9225649876911
x6=62.0464549083984x_{6} = -62.0464549083984
x7=40.0553063332699x_{7} = -40.0553063332699
x8=30.6305283725005x_{8} = -30.6305283725005
x9=228.550865548657x_{9} = -228.550865548657
x10=21.2057504115129x_{10} = -21.2057504115129
x11=2.32149445348489x_{11} = -2.32149445348489
x12=43.1968989868597x_{12} = -43.1968989868597
x13=33.7721210260903x_{13} = -33.7721210260903
x14=49.4800842940392x_{14} = -49.4800842940392
x15=5.49923314463276x_{15} = -5.49923314463276
x16=58.9048622548086x_{16} = -58.9048622548086
x17=68.329640215578x_{17} = -68.329640215578
x18=11.7809751551847x_{18} = -11.7809751551847
x19=84.037603483527x_{19} = -84.037603483527
x20=24.3473430653303x_{20} = -24.3473430653303
x21=18.0641577631913x_{21} = -18.0641577631913
x22=27.4889357189103x_{22} = -27.4889357189103
x23=46.3384916404494x_{23} = -46.3384916404494
x24=96.6039740978861x_{24} = -96.6039740978861
x25=90.3207887907066x_{25} = -90.3207887907066
x26=74.6128255227576x_{26} = -74.6128255227576
x27=55.7632696012188x_{27} = -55.7632696012188
x28=93.4623814442964x_{28} = -93.4623814442964
x29=71.4712328691678x_{29} = -71.4712328691678
x30=52.621676947629x_{30} = -52.621676947629
x31=99.7455667514759x_{31} = -99.7455667514759
x32=36.9137136796801x_{32} = -36.9137136796801
x33=80.8960108299372x_{33} = -80.8960108299372
x34=87.1791961371168x_{34} = -87.1791961371168
x35=77.7544181763474x_{35} = -77.7544181763474
Puntos de cruce con el eje de coordenadas Y
El gráfico cruce el eje Y cuando x es igual a 0:
sustituimos x = 0 en exp(x)/2 - cos(x) + sin(x).
(cos(0)+e02)+sin(0)\left(- \cos{\left(0 \right)} + \frac{e^{0}}{2}\right) + \sin{\left(0 \right)}
Resultado:
f(0)=12f{\left(0 \right)} = - \frac{1}{2}
Punto:
(0, -1/2)
Extremos de la función
Para hallar los extremos hay que resolver la ecuación
ddxf(x)=0\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:
ddxf(x)=\frac{d}{d x} f{\left(x \right)} =
primera derivada
ex2+sin(x)+cos(x)=0\frac{e^{x}}{2} + \sin{\left(x \right)} + \cos{\left(x \right)} = 0
Resolvermos esta ecuación
Raíces de esta ecuación
x1=35.3429173528852x_{1} = -35.3429173528852
x2=51.0508806208341x_{2} = -51.0508806208341
x3=107.59954838545x_{3} = -107.59954838545
x4=16.4933614070535x_{4} = -16.4933614070535
x5=0.925925557386978x_{5} = -0.925925557386978
x6=10.2101631153588x_{6} = -10.2101631153588
x7=98.174770424681x_{7} = -98.174770424681
x8=13.3517693399106x_{8} = -13.3517693399106
x9=38.484510006475x_{9} = -38.484510006475
x10=79.3252145031423x_{10} = -79.3252145031423
x11=88.7499924639117x_{11} = -88.7499924639117
x12=3.91997570268469x_{12} = -3.91997570268469
x13=66.7588438887831x_{13} = -66.7588438887831
x14=63.6172512351933x_{14} = -63.6172512351933
x15=25.9181393921178x_{15} = -25.9181393921178
x16=95.0331777710912x_{16} = -95.0331777710912
x17=32.2013246992954x_{17} = -32.2013246992954
x18=47.9092879672443x_{18} = -47.9092879672443
x19=73.0420291959627x_{19} = -73.0420291959627
x20=41.6261026600648x_{20} = -41.6261026600648
x21=7.06888440891705x_{21} = -7.06888440891705
x22=91.8915851175014x_{22} = -91.8915851175014
x23=82.4668071567321x_{23} = -82.4668071567321
x24=76.1836218495525x_{24} = -76.1836218495525
x25=22.7765467384806x_{25} = -22.7765467384806
x26=60.4756585816035x_{26} = -60.4756585816035
x27=29.0597320457055x_{27} = -29.0597320457055
x28=19.634954085986x_{28} = -19.634954085986
x29=69.9004365423729x_{29} = -69.9004365423729
x30=57.3340659280137x_{30} = -57.3340659280137
x31=44.7676953136546x_{31} = -44.7676953136546
x32=54.1924732744239x_{32} = -54.1924732744239
x33=85.6083998103219x_{33} = -85.6083998103219
Signos de extremos en los puntos:
(-35.34291735288517, 1.4142135623731)

(-51.05088062083414, -1.41421356237309)

(-107.59954838545042, -1.41421356237309)

(-16.493361407053527, 1.41421359672843)

(-0.9259255573869776, -1.20219033071629)

(-10.210163115358759, 1.41423195948623)

(-98.17477042468104, 1.41421356237309)

(-13.351769339910561, -1.41421276736715)

(-38.48451000647497, -1.41421356237309)

(-79.32521450314228, 1.41421356237309)

(-88.74999246391165, -1.4142135623731)

(-3.919975702684686, 1.42409955291581)

(-66.7588438887831, 1.4142135623731)

(-63.617251235193315, -1.41421356237309)

(-25.918139392117755, -1.41421356237032)

(-95.03317777109125, -1.41421356237309)

(-32.201324699295384, -1.41421356237309)

(-47.909287967244346, 1.41421356237309)

(-73.0420291959627, 1.41421356237309)

(-41.62610266006476, 1.41421356237309)

(-7.068884408917046, -1.4137879072593)

(-91.89158511750145, 1.41421356237309)

(-82.46680715673207, -1.41421356237309)

(-76.18362184955248, -1.41421356237309)

(-22.776546738480636, 1.41421356243725)

(-60.47565858160352, 1.41421356237309)

(-29.059732045705502, 1.41421356237321)

(-19.634954085986, -1.41421356088847)

(-69.9004365423729, -1.4142135623731)

(-57.33406592801373, -1.41421356237309)

(-44.767695313654556, -1.41421356237309)

(-54.19247327442393, 1.41421356237309)

(-85.60839981032187, 1.41421356237309)


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:
x1=51.0508806208341x_{1} = -51.0508806208341
x2=107.59954838545x_{2} = -107.59954838545
x3=0.925925557386978x_{3} = -0.925925557386978
x4=13.3517693399106x_{4} = -13.3517693399106
x5=38.484510006475x_{5} = -38.484510006475
x6=88.7499924639117x_{6} = -88.7499924639117
x7=63.6172512351933x_{7} = -63.6172512351933
x8=25.9181393921178x_{8} = -25.9181393921178
x9=95.0331777710912x_{9} = -95.0331777710912
x10=32.2013246992954x_{10} = -32.2013246992954
x11=7.06888440891705x_{11} = -7.06888440891705
x12=82.4668071567321x_{12} = -82.4668071567321
x13=76.1836218495525x_{13} = -76.1836218495525
x14=19.634954085986x_{14} = -19.634954085986
x15=69.9004365423729x_{15} = -69.9004365423729
x16=57.3340659280137x_{16} = -57.3340659280137
x17=44.7676953136546x_{17} = -44.7676953136546
Puntos máximos de la función:
x17=35.3429173528852x_{17} = -35.3429173528852
x17=16.4933614070535x_{17} = -16.4933614070535
x17=10.2101631153588x_{17} = -10.2101631153588
x17=98.174770424681x_{17} = -98.174770424681
x17=79.3252145031423x_{17} = -79.3252145031423
x17=3.91997570268469x_{17} = -3.91997570268469
x17=66.7588438887831x_{17} = -66.7588438887831
x17=47.9092879672443x_{17} = -47.9092879672443
x17=73.0420291959627x_{17} = -73.0420291959627
x17=41.6261026600648x_{17} = -41.6261026600648
x17=91.8915851175014x_{17} = -91.8915851175014
x17=22.7765467384806x_{17} = -22.7765467384806
x17=60.4756585816035x_{17} = -60.4756585816035
x17=29.0597320457055x_{17} = -29.0597320457055
x17=54.1924732744239x_{17} = -54.1924732744239
x17=85.6083998103219x_{17} = -85.6083998103219
Decrece en los intervalos
[0.925925557386978,)\left[-0.925925557386978, \infty\right)
Crece en los intervalos
(,107.59954838545]\left(-\infty, -107.59954838545\right]
Puntos de flexiones
Hallemos los puntos de flexiones, para eso hay que resolver la ecuación
d2dx2f(x)=0\frac{d^{2}}{d x^{2}} f{\left(x \right)} = 0
(la segunda derivada es igual a cero),
las raíces de la ecuación obtenida serán los puntos de flexión para el gráfico de la función indicado:
d2dx2f(x)=\frac{d^{2}}{d x^{2}} f{\left(x \right)} =
segunda derivada
ex2sin(x)+cos(x)=0\frac{e^{x}}{2} - \sin{\left(x \right)} + \cos{\left(x \right)} = 0
Resolvermos esta ecuación
Raíces de esta ecuación
x1=65.1880475619882x_{1} = -65.1880475619882
x2=18.0641577530913x_{2} = -18.0641577530913
x3=62.0464549083984x_{3} = -62.0464549083984
x4=40.0553063332699x_{4} = -40.0553063332699
x5=228.550865548657x_{5} = -228.550865548657
x6=8.63944237121926x_{6} = -8.63944237121926
x7=43.1968989868597x_{7} = -43.1968989868597
x8=33.7721210260903x_{8} = -33.7721210260903
x9=49.4800842940392x_{9} = -49.4800842940392
x10=58.9048622548086x_{10} = -58.9048622548086
x11=68.329640215578x_{11} = -68.329640215578
x12=27.4889357189111x_{12} = -27.4889357189111
x13=84.037603483527x_{13} = -84.037603483527
x14=30.6305283725005x_{14} = -30.6305283725005
x15=21.2057504119493x_{15} = -21.2057504119493
x16=2.3886402485139x_{16} = -2.3886402485139
x17=5.49633694895682x_{17} = -5.49633694895682
x18=46.3384916404494x_{18} = -46.3384916404494
x19=11.7809697467241x_{19} = -11.7809697467241
x20=96.6039740978861x_{20} = -96.6039740978861
x21=90.3207887907066x_{21} = -90.3207887907066
x22=74.6128255227576x_{22} = -74.6128255227576
x23=55.7632696012188x_{23} = -55.7632696012188
x24=24.3473430653115x_{24} = -24.3473430653115
x25=93.4623814442964x_{25} = -93.4623814442964
x26=71.4712328691678x_{26} = -71.4712328691678
x27=52.621676947629x_{27} = -52.621676947629
x28=99.7455667514759x_{28} = -99.7455667514759
x29=36.9137136796801x_{29} = -36.9137136796801
x30=80.8960108299372x_{30} = -80.8960108299372
x31=87.1791961371168x_{31} = -87.1791961371168
x32=14.9225652214119x_{32} = -14.9225652214119
x33=77.7544181763474x_{33} = -77.7544181763474

Intervalos de convexidad y concavidad:
Hallemos los intervales donde la función es convexa o cóncava, para eso veamos cómo se comporta la función en los puntos de flexiones:
Cóncava en los intervalos
[2.3886402485139,)\left[-2.3886402485139, \infty\right)
Convexa en los intervalos
(,228.550865548657]\left(-\infty, -228.550865548657\right]
Asíntotas horizontales
Hallemos las asíntotas horizontales mediante los límites de esta función con x->+oo y x->-oo
limx((ex2cos(x))+sin(x))=2,2\lim_{x \to -\infty}\left(\left(\frac{e^{x}}{2} - \cos{\left(x \right)}\right) + \sin{\left(x \right)}\right) = \left\langle -2, 2\right\rangle
Tomamos como el límite
es decir,
ecuación de la asíntota horizontal a la izquierda:
y=2,2y = \left\langle -2, 2\right\rangle
limx((ex2cos(x))+sin(x))=\lim_{x \to \infty}\left(\left(\frac{e^{x}}{2} - \cos{\left(x \right)}\right) + \sin{\left(x \right)}\right) = \infty
Tomamos como el límite
es decir,
no hay asíntota horizontal a la derecha
Asíntotas inclinadas
Se puede hallar la asíntota inclinada calculando el límite de la función exp(x)/2 - cos(x) + sin(x), dividida por x con x->+oo y x ->-oo
limx((ex2cos(x))+sin(x)x)=0\lim_{x \to -\infty}\left(\frac{\left(\frac{e^{x}}{2} - \cos{\left(x \right)}\right) + \sin{\left(x \right)}}{x}\right) = 0
Tomamos como el límite
es decir,
la inclinada coincide con la asíntota horizontal a la derecha
limx((ex2cos(x))+sin(x)x)=\lim_{x \to \infty}\left(\frac{\left(\frac{e^{x}}{2} - \cos{\left(x \right)}\right) + \sin{\left(x \right)}}{x}\right) = \infty
Tomamos como el límite
es decir,
no hay asíntota inclinada a la derecha
Paridad e imparidad de la función
Comprobemos si la función es par o impar mediante las relaciones f = f(-x) и f = -f(-x).
Pues, comprobamos:
(ex2cos(x))+sin(x)=sin(x)cos(x)+ex2\left(\frac{e^{x}}{2} - \cos{\left(x \right)}\right) + \sin{\left(x \right)} = - \sin{\left(x \right)} - \cos{\left(x \right)} + \frac{e^{- x}}{2}
- No
(ex2cos(x))+sin(x)=sin(x)+cos(x)ex2\left(\frac{e^{x}}{2} - \cos{\left(x \right)}\right) + \sin{\left(x \right)} = \sin{\left(x \right)} + \cos{\left(x \right)} - \frac{e^{- x}}{2}
- No
es decir, función
no es
par ni impar