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cos(x)/8+cos(3*x)+sin(3*x)

Gráfico de la función y = cos(x)/8+cos(3*x)+sin(3*x)

v

Gráfico:

interior superior

Puntos de intersección:

mostrar?

Definida a trozos:

Solución

Ha introducido [src]
       cos(x)                      
f(x) = ------ + cos(3*x) + sin(3*x)
         8                         
f(x)=(cos(x)8+cos(3x))+sin(3x)f{\left(x \right)} = \left(\frac{\cos{\left(x \right)}}{8} + \cos{\left(3 x \right)}\right) + \sin{\left(3 x \right)}
f = cos(x)/8 + cos(3*x) + sin(3*x)
Gráfico de la función
02468-8-6-4-2-10105-5
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:
(cos(x)8+cos(3x))+sin(3x)=0\left(\frac{\cos{\left(x \right)}}{8} + \cos{\left(3 x \right)}\right) + \sin{\left(3 x \right)} = 0
Resolvermos esta ecuación
Puntos de cruce con el eje X:

Solución numérica
x1=84.5329364151724x_{1} = 84.5329364151724
x2=100.240899683121x_{2} = 100.240899683121
x3=53.6971403427785x_{3} = -53.6971403427785
x4=29.5754814187805x_{4} = -29.5754814187805
x5=88.2546595322662x_{5} = -88.2546595322662
x6=40.0348898918404x_{6} = -40.0348898918404
x7=1.30114753647236x_{7} = -1.30114753647236
x8=260.462125016201x_{8} = 260.462125016201
x9=9.71484319252137x_{9} = -9.71484319252137
x10=52.1059275745541x_{10} = 52.1059275745541
x11=98.1951868661105x_{11} = 98.1951868661105
x12=90.3003723492771x_{12} = -90.3003723492771
x13=49.9754172256847x_{13} = 49.9754172256847
x14=39.0002593795499x_{14} = -39.0002593795499
x15=59.9803256499581x_{15} = -59.9803256499581
x16=87.6745290687622x_{16} = 87.6745290687622
x17=10.2305925655963x_{17} = 10.2305925655963
x18=3.9474072584167x_{18} = 3.9474072584167
x19=7.58433284365195x_{19} = -7.58433284365195
x20=68.3092237741485x_{20} = -68.3092237741485
x21=21.7010833433766x_{21} = 21.7010833433766
x22=74.5924090813281x_{22} = -74.5924090813281
x23=75.688288917907x_{23} = -75.688288917907
x24=5.47737070235268x_{24} = -5.47737070235268
x25=34.2674539577357x_{25} = 34.2674539577357
x26=47.9297044086738x_{26} = 47.9297044086738
x27=84.0171870420975x_{27} = -84.0171870420975
x28=23.831593692246x_{28} = 23.831593692246
x29=69.9208529838023x_{29} = 69.9208529838023
x30=54.2128897158534x_{30} = 54.2128897158534
x31=56.2586025328643x_{31} = 56.2586025328643
x32=74.0970761496827x_{32} = 74.0970761496827
x33=30.1147789994256x_{33} = 30.1147789994256
x34=25.9385558335452x_{34} = 25.9385558335452
x35=36.3979643066052x_{35} = 36.3979643066052
x36=95.5489271441662x_{36} = -95.5489271441662
x37=8.12363042429702x_{37} = 8.12363042429702
x38=41.6465191014942x_{38} = 41.6465191014942
x39=76.2040382909819x_{39} = 76.2040382909819
x40=71.9665658008133x_{40} = 71.9665658008133
x41=43.6922319185051x_{41} = 43.6922319185051
x42=100.821030146625x_{42} = -100.821030146625
x43=27.9842686505561x_{43} = 27.9842686505561
x44=22.2812138068805x_{44} = -22.2812138068805
x45=71.4508164277383x_{45} = -71.4508164277383
x46=81.9714742250866x_{46} = -81.9714742250866
x47=79.8409638762172x_{47} = -79.8409638762172
x48=58.3891128817337x_{48} = 58.3891128817337
x49=91.9120015589309x_{49} = 91.9120015589309
x50=44.2723623820091x_{50} = -44.2723623820091
x51=13.8675181508315x_{51} = -13.8675181508315
x52=82.4872235981615x_{52} = 82.4872235981615
x53=1.84044511711743x_{53} = 1.84044511711743
x54=55.7428531597894x_{54} = -55.7428531597894
x55=19.6553705263657x_{55} = 19.6553705263657
x56=62.5417878400439x_{56} = 62.5417878400439
x57=26.4338887651907x_{57} = -26.4338887651907
x58=73.5577785690376x_{58} = -73.5577785690376
x59=62.026038466969x_{59} = -62.026038466969
x60=12.2763053826072x_{60} = 12.2763053826072
x61=0.290065231751989x_{61} = -0.290065231751989
x62=38.5049264479044x_{62} = 38.5049264479044
x63=47.4139550355989x_{63} = -47.4139550355989
x64=31.7059917676499x_{64} = -31.7059917676499
x65=14.4068157314766x_{65} = 14.4068157314766
x66=18.0437413167119x_{66} = -18.0437413167119
x67=96.0882247248112x_{67} = 96.0882247248112
x68=89.8050394176316x_{68} = 89.8050394176316
x69=78.2497511079928x_{69} = 78.2497511079928
x70=99.7251503100465x_{70} = -99.7251503100465
x71=97.6794374930356x_{71} = -97.6794374930356
x72=64.1330006082682x_{72} = -64.1330006082682
x73=35.8586667259601x_{73} = -35.8586667259601
x74=37.9891770748295x_{74} = -37.9891770748295
x75=60.496075023033x_{75} = 60.496075023033
x76=57.8498153010886x_{76} = -57.8498153010886
x77=67.8138908425031x_{77} = 67.8138908425031
x78=15.998028499701x_{78} = -15.998028499701
x79=45.8227422673745x_{79} = 45.8227422673745
x80=42.1418520331397x_{80} = -42.1418520331397
x81=93.4419650028669x_{81} = -93.4419650028669
x82=32.2217411407248x_{82} = 32.2217411407248
x83=33.7517045846608x_{83} = -33.7517045846608
x84=80.3802614568623x_{84} = 80.3802614568623
x85=11.7605560095323x_{85} = -11.7605560095323
x86=66.2635109571376x_{86} = -66.2635109571376
x87=49.4596678526098x_{87} = -49.4596678526098
x88=51.5666299939091x_{88} = -51.5666299939091
x89=20.1507034580111x_{89} = -20.1507034580111
x90=52.6012605061996x_{90} = -52.6012605061996
x91=86.1241491833968x_{91} = -86.1241491833968
x92=65.6833804936337x_{92} = 65.6833804936337
x93=5.9931200754276x_{93} = 5.9931200754276
x94=16.5137778727759x_{94} = 16.5137778727759
x95=314.965079963806x_{95} = 314.965079963806
x96=27.4685192774812x_{96} = -27.4685192774812
x97=41.1307697284193x_{97} = -41.1307697284193
x98=93.9577143759418x_{98} = 93.9577143759418
x99=77.7340017349179x_{99} = -77.7340017349179
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 cos(x)/8 + cos(3*x) + sin(3*x).
sin(03)+(cos(0)8+cos(03))\sin{\left(0 \cdot 3 \right)} + \left(\frac{\cos{\left(0 \right)}}{8} + \cos{\left(0 \cdot 3 \right)}\right)
Resultado:
f(0)=98f{\left(0 \right)} = \frac{9}{8}
Punto:
(0, 9/8)
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
sin(x)83sin(3x)+3cos(3x)=0- \frac{\sin{\left(x \right)}}{8} - 3 \sin{\left(3 x \right)} + 3 \cos{\left(3 x \right)} = 0
Resolvermos esta ecuación
Soluciones no halladas,
tal vez la función no tenga extremos
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
(9sin(3x)+cos(x)8+9cos(3x))=0- (9 \sin{\left(3 x \right)} + \frac{\cos{\left(x \right)}}{8} + 9 \cos{\left(3 x \right)}) = 0
Resolvermos esta ecuación
Soluciones no halladas,
tal vez la función no tenga flexiones
Asíntotas horizontales
Hallemos las asíntotas horizontales mediante los límites de esta función con x->+oo y x->-oo
limx((cos(x)8+cos(3x))+sin(3x))=178,178\lim_{x \to -\infty}\left(\left(\frac{\cos{\left(x \right)}}{8} + \cos{\left(3 x \right)}\right) + \sin{\left(3 x \right)}\right) = \left\langle - \frac{17}{8}, \frac{17}{8}\right\rangle
Tomamos como el límite
es decir,
ecuación de la asíntota horizontal a la izquierda:
y=178,178y = \left\langle - \frac{17}{8}, \frac{17}{8}\right\rangle
limx((cos(x)8+cos(3x))+sin(3x))=178,178\lim_{x \to \infty}\left(\left(\frac{\cos{\left(x \right)}}{8} + \cos{\left(3 x \right)}\right) + \sin{\left(3 x \right)}\right) = \left\langle - \frac{17}{8}, \frac{17}{8}\right\rangle
Tomamos como el límite
es decir,
ecuación de la asíntota horizontal a la derecha:
y=178,178y = \left\langle - \frac{17}{8}, \frac{17}{8}\right\rangle
Asíntotas inclinadas
Se puede hallar la asíntota inclinada calculando el límite de la función cos(x)/8 + cos(3*x) + sin(3*x), dividida por x con x->+oo y x ->-oo
limx((cos(x)8+cos(3x))+sin(3x)x)=0\lim_{x \to -\infty}\left(\frac{\left(\frac{\cos{\left(x \right)}}{8} + \cos{\left(3 x \right)}\right) + \sin{\left(3 x \right)}}{x}\right) = 0
Tomamos como el límite
es decir,
la inclinada coincide con la asíntota horizontal a la derecha
limx((cos(x)8+cos(3x))+sin(3x)x)=0\lim_{x \to \infty}\left(\frac{\left(\frac{\cos{\left(x \right)}}{8} + \cos{\left(3 x \right)}\right) + \sin{\left(3 x \right)}}{x}\right) = 0
Tomamos como el límite
es decir,
la inclinada coincide con la asíntota horizontal a la izquierda
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:
(cos(x)8+cos(3x))+sin(3x)=sin(3x)+cos(x)8+cos(3x)\left(\frac{\cos{\left(x \right)}}{8} + \cos{\left(3 x \right)}\right) + \sin{\left(3 x \right)} = - \sin{\left(3 x \right)} + \frac{\cos{\left(x \right)}}{8} + \cos{\left(3 x \right)}
- No
(cos(x)8+cos(3x))+sin(3x)=sin(3x)cos(x)8cos(3x)\left(\frac{\cos{\left(x \right)}}{8} + \cos{\left(3 x \right)}\right) + \sin{\left(3 x \right)} = \sin{\left(3 x \right)} - \frac{\cos{\left(x \right)}}{8} - \cos{\left(3 x \right)}
- No
es decir, función
no es
par ni impar
Gráfico
Gráfico de la función y = cos(x)/8+cos(3*x)+sin(3*x)