Sr Examen

Gráfico de la función y = (2*x+1)*sin(x)

v

Gráfico:

interior superior

Puntos de intersección:

mostrar?

Definida a trozos:

Solución

Ha introducido [src]
f(x) = (2*x + 1)*sin(x)
$$f{\left(x \right)} = \left(2 x + 1\right) \sin{\left(x \right)}$$
f = (2*x + 1)*sin(x)
Gráfico de la función
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:
$$\left(2 x + 1\right) \sin{\left(x \right)} = 0$$
Resolvermos esta ecuación
Puntos de cruce con el eje X:

Solución analítica
$$x_{1} = - \frac{1}{2}$$
$$x_{2} = 0$$
$$x_{3} = \pi$$
Solución numérica
$$x_{1} = 69.1150383789755$$
$$x_{2} = 65.9734457253857$$
$$x_{3} = -91.106186954104$$
$$x_{4} = -59.6902604182061$$
$$x_{5} = -21.9911485751286$$
$$x_{6} = 12.5663706143592$$
$$x_{7} = 21.9911485751286$$
$$x_{8} = -69.1150383789755$$
$$x_{9} = -100.530964914873$$
$$x_{10} = 3.14159265358979$$
$$x_{11} = -3.14159265358979$$
$$x_{12} = -25.1327412287183$$
$$x_{13} = -15.707963267949$$
$$x_{14} = -53.4070751110265$$
$$x_{15} = -72.2566310325652$$
$$x_{16} = 84.8230016469244$$
$$x_{17} = -81.6814089933346$$
$$x_{18} = -94.2477796076938$$
$$x_{19} = -0.5$$
$$x_{20} = 18.8495559215388$$
$$x_{21} = -65.9734457253857$$
$$x_{22} = 94.2477796076938$$
$$x_{23} = 9.42477796076938$$
$$x_{24} = -40.8407044966673$$
$$x_{25} = 34.5575191894877$$
$$x_{26} = 0$$
$$x_{27} = 97.3893722612836$$
$$x_{28} = 53.4070751110265$$
$$x_{29} = -62.8318530717959$$
$$x_{30} = 59.6902604182061$$
$$x_{31} = -28.2743338823081$$
$$x_{32} = -56.5486677646163$$
$$x_{33} = 91.106186954104$$
$$x_{34} = 15.707963267949$$
$$x_{35} = -18.8495559215388$$
$$x_{36} = 6.28318530717959$$
$$x_{37} = 56.5486677646163$$
$$x_{38} = 87.9645943005142$$
$$x_{39} = 31.4159265358979$$
$$x_{40} = -1036.72557568463$$
$$x_{41} = 25.1327412287183$$
$$x_{42} = 43.9822971502571$$
$$x_{43} = -47.1238898038469$$
$$x_{44} = 72.2566310325652$$
$$x_{45} = -34.5575191894877$$
$$x_{46} = -97.3893722612836$$
$$x_{47} = -50.2654824574367$$
$$x_{48} = 100.530964914873$$
$$x_{49} = 81.6814089933346$$
$$x_{50} = -75.398223686155$$
$$x_{51} = 40.8407044966673$$
$$x_{52} = -9.42477796076938$$
$$x_{53} = 78.5398163397448$$
$$x_{54} = -87.9645943005142$$
$$x_{55} = 37.6991118430775$$
$$x_{56} = -78.5398163397448$$
$$x_{57} = -6.28318530717959$$
$$x_{58} = 50.2654824574367$$
$$x_{59} = -37.6991118430775$$
$$x_{60} = -43.9822971502571$$
$$x_{61} = 47.1238898038469$$
$$x_{62} = 28.2743338823081$$
$$x_{63} = 62.8318530717959$$
$$x_{64} = -31.4159265358979$$
$$x_{65} = -12.5663706143592$$
$$x_{66} = 75.398223686155$$
$$x_{67} = -84.8230016469244$$
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 (2*x + 1)*sin(x).
$$\left(0 \cdot 2 + 1\right) \sin{\left(0 \right)}$$
Resultado:
$$f{\left(0 \right)} = 0$$
Punto:
(0, 0)
Extremos de la función
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
$$\left(2 x + 1\right) \cos{\left(x \right)} + 2 \sin{\left(x \right)} = 0$$
Resolvermos esta ecuación
Raíces de esta ecuación
$$x_{1} = 39.2950316476879$$
$$x_{2} = 92.6877138973701$$
$$x_{3} = -7.98676475119172$$
$$x_{4} = -33.0174658775265$$
$$x_{5} = 67.5589341430727$$
$$x_{6} = -67.5591531543674$$
$$x_{7} = -80.1231711644351$$
$$x_{8} = 7.97148100902349$$
$$x_{9} = 76.9819255322054$$
$$x_{10} = 83.2641430354848$$
$$x_{11} = -95.829065529839$$
$$x_{12} = 58.1365166573738$$
$$x_{13} = -39.2956785303244$$
$$x_{14} = -83.2642872382528$$
$$x_{15} = -26.7416265193495$$
$$x_{16} = 80.123015436615$$
$$x_{17} = -11.0897262388501$$
$$x_{18} = 20.4680078422429$$
$$x_{19} = 29.8780368458978$$
$$x_{20} = 54.9958888407247$$
$$x_{21} = -64.4182930958041$$
$$x_{22} = 95.8289566560771$$
$$x_{23} = -92.6878302742345$$
$$x_{24} = 89.5464955446878$$
$$x_{25} = 51.8553766970605$$
$$x_{26} = 4.89564432915531$$
$$x_{27} = 26.7402314854239$$
$$x_{28} = 48.7150023424838$$
$$x_{29} = 42.4347877496486$$
$$x_{30} = -36.1563536592178$$
$$x_{31} = -70.700078740623$$
$$x_{32} = 36.1555897201517$$
$$x_{33} = -4.93419822854993$$
$$x_{34} = -20.4703846071522$$
$$x_{35} = 61.2772425220152$$
$$x_{36} = 17.3347711916489$$
$$x_{37} = -29.8791548121049$$
$$x_{38} = 23.6034090301611$$
$$x_{39} = -14.2099775813926$$
$$x_{40} = 33.0165500205799$$
$$x_{41} = -76.9820942237331$$
$$x_{42} = -42.4353425392198$$
$$x_{43} = -45.5752749499286$$
$$x_{44} = 105.252809626976$$
$$x_{45} = 86.4053042434102$$
$$x_{46} = -86.4054381545562$$
$$x_{47} = -54.9962192754584$$
$$x_{48} = -48.715423408888$$
$$x_{49} = 70.699878750109$$
$$x_{50} = 45.5747939110765$$
$$x_{51} = -73.8410614412353$$
$$x_{52} = 1.95728275422062$$
$$x_{53} = 11.0817037582484$$
$$x_{54} = -61.2775087154266$$
$$x_{55} = 98.9702215094204$$
$$x_{56} = -98.9703235828905$$
$$x_{57} = -89.5466202277414$$
$$x_{58} = -23.6051982121417$$
$$x_{59} = -58.1368123734526$$
$$x_{60} = -0.247412484885142$$
$$x_{61} = -17.3380791158534$$
$$x_{62} = 14.2050661771509$$
$$x_{63} = 64.4180522161792$$
$$x_{64} = 73.8408780976001$$
$$x_{65} = -2.12300090681457$$
$$x_{66} = -51.8557483406994$$
Signos de extremos en los puntos:
(39.29503164768789, 79.5649464248379)

(92.68771389737012, -186.364697693097)

(-7.986764751191716, 14.8417215197729)

(-33.01746587752653, 65.0042008467558)

(67.5589341430727, -136.103177516664)

(-67.55915315436735, -134.103396587937)

(-80.12317116443509, -159.233784656253)

(7.971481009023492, 16.8261383769496)

(76.98192553220542, 154.950946440755)

(83.26414303548475, 167.516349064459)

(-95.82906552983897, 190.647641945238)

(58.13651665737381, 117.255982814905)

(-39.2956785303244, 77.5655938310989)

(-83.2642872382528, 165.516493293226)

(-26.741626519349484, 52.4451870984841)

(80.12301543661505, -161.233628898112)

(-11.089726238850124, -21.0856482225243)

(20.46800784224292, 41.8884051837394)

(29.878036845897785, -60.7231819016979)

(54.995888840724724, -110.973762715585)

(-64.41829309580406, 127.820944089557)

(95.8289566560771, 192.647533056656)

(-92.68783027423446, -184.364814086894)

(89.54649554468782, 180.081886742599)

(51.85537669706051, 104.691658383599)

(4.895644329155311, -10.6105958362832)

(26.740231485423934, 54.4437896263579)

(48.715002342483764, -98.4096919670489)

(42.4347877496486, -85.8462938347437)

(-36.156353659217835, -71.2846783594538)

(-70.70007874062303, 140.385914650559)

(36.15558972015174, -73.283913689973)

(-4.934198228549927, -8.65112979640719)

(-20.470384607152152, 39.8907890373943)

(61.2772425220152, -123.538301033815)

(17.334771191648883, -35.6136040006033)

(-29.879154812104865, -58.7243014330717)

(23.60340903016115, -48.165383634478)

(-14.209977581392641, 27.3473053378206)

(33.016550020579906, 67.0032839397468)

(-76.98209422373313, 152.951115167863)

(-42.43534253921977, -83.8468490094031)

(-45.575274949928605, 90.1283729743018)

(105.25280962697555, -211.496163874502)

(86.40530424341024, -173.799102851863)

(-86.40543815455618, -171.799236785429)

(-54.99621927545844, -108.974093286877)

(-48.71542340888797, -96.4101132552267)

(70.69987875010902, 142.385714610033)

(45.5747939110765, 92.1278916459743)

(-73.84106144123533, -146.668489856598)

(1.9572827542206206, 4.55206306571846)

(11.081703758248404, -23.0775442284508)

(-61.27750871542658, -121.538567315839)

(98.9702215094204, -198.930390520815)

(-98.97032358289053, -196.930492607311)

(-89.54662022774141, 178.082011445089)

(-23.605198212141747, -46.1671768296396)

(-58.13681237345261, 115.256278640346)

(-0.2474124848851423, -0.123715373656181)

(-17.338079115853432, -33.6169256769223)

(14.20506617715089, 29.3423635380666)

(64.41805221617925, 129.820703137375)

(73.8408780976001, -148.668306470931)

(-2.123000906814568, 2.76354903624568)

(-51.85574834069936, 102.692030199991)


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:
$$x_{1} = 92.6877138973701$$
$$x_{2} = 67.5589341430727$$
$$x_{3} = -67.5591531543674$$
$$x_{4} = -80.1231711644351$$
$$x_{5} = 80.123015436615$$
$$x_{6} = -11.0897262388501$$
$$x_{7} = 29.8780368458978$$
$$x_{8} = 54.9958888407247$$
$$x_{9} = -92.6878302742345$$
$$x_{10} = 4.89564432915531$$
$$x_{11} = 48.7150023424838$$
$$x_{12} = 42.4347877496486$$
$$x_{13} = -36.1563536592178$$
$$x_{14} = 36.1555897201517$$
$$x_{15} = -4.93419822854993$$
$$x_{16} = 61.2772425220152$$
$$x_{17} = 17.3347711916489$$
$$x_{18} = -29.8791548121049$$
$$x_{19} = 23.6034090301611$$
$$x_{20} = -42.4353425392198$$
$$x_{21} = 105.252809626976$$
$$x_{22} = 86.4053042434102$$
$$x_{23} = -86.4054381545562$$
$$x_{24} = -54.9962192754584$$
$$x_{25} = -48.715423408888$$
$$x_{26} = -73.8410614412353$$
$$x_{27} = 11.0817037582484$$
$$x_{28} = -61.2775087154266$$
$$x_{29} = 98.9702215094204$$
$$x_{30} = -98.9703235828905$$
$$x_{31} = -23.6051982121417$$
$$x_{32} = -0.247412484885142$$
$$x_{33} = -17.3380791158534$$
$$x_{34} = 73.8408780976001$$
Puntos máximos de la función:
$$x_{34} = 39.2950316476879$$
$$x_{34} = -7.98676475119172$$
$$x_{34} = -33.0174658775265$$
$$x_{34} = 7.97148100902349$$
$$x_{34} = 76.9819255322054$$
$$x_{34} = 83.2641430354848$$
$$x_{34} = -95.829065529839$$
$$x_{34} = 58.1365166573738$$
$$x_{34} = -39.2956785303244$$
$$x_{34} = -83.2642872382528$$
$$x_{34} = -26.7416265193495$$
$$x_{34} = 20.4680078422429$$
$$x_{34} = -64.4182930958041$$
$$x_{34} = 95.8289566560771$$
$$x_{34} = 89.5464955446878$$
$$x_{34} = 51.8553766970605$$
$$x_{34} = 26.7402314854239$$
$$x_{34} = -70.700078740623$$
$$x_{34} = -20.4703846071522$$
$$x_{34} = -14.2099775813926$$
$$x_{34} = 33.0165500205799$$
$$x_{34} = -76.9820942237331$$
$$x_{34} = -45.5752749499286$$
$$x_{34} = 70.699878750109$$
$$x_{34} = 45.5747939110765$$
$$x_{34} = 1.95728275422062$$
$$x_{34} = -89.5466202277414$$
$$x_{34} = -58.1368123734526$$
$$x_{34} = 14.2050661771509$$
$$x_{34} = 64.4180522161792$$
$$x_{34} = -2.12300090681457$$
$$x_{34} = -51.8557483406994$$
Decrece en los intervalos
$$\left[105.252809626976, \infty\right)$$
Crece en los intervalos
$$\left(-\infty, -98.9703235828905\right]$$
Puntos de flexiones
Hallemos los puntos de flexiones, para eso hay que resolver la ecuación
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = 0$$
(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:
$$\frac{d^{2}}{d x^{2}} f{\left(x \right)} = $$
segunda derivada
$$- \left(2 x + 1\right) \sin{\left(x \right)} + 4 \cos{\left(x \right)} = 0$$
Resolvermos esta ecuación
Raíces de esta ecuación
$$x_{1} = -1.22363340679195$$
$$x_{2} = 6.55926589110157$$
$$x_{3} = 0.945096917005164$$
$$x_{4} = 44.0271833632886$$
$$x_{5} = -91.128251546449$$
$$x_{6} = -15.8376298773678$$
$$x_{7} = -59.7240176727685$$
$$x_{8} = -78.5654302714376$$
$$x_{9} = -44.0282120696665$$
$$x_{10} = -37.7527476656581$$
$$x_{11} = 78.5651065552681$$
$$x_{12} = -81.7060327275283$$
$$x_{13} = 25.2103744983198$$
$$x_{14} = -22.0835478883776$$
$$x_{15} = 62.8634065553665$$
$$x_{16} = -25.2134927005181$$
$$x_{17} = -6.60000933977149$$
$$x_{18} = -100.550952067693$$
$$x_{19} = 100.550754365473$$
$$x_{20} = 66.0035102644062$$
$$x_{21} = -47.1667206869961$$
$$x_{22} = -31.4803940350564$$
$$x_{23} = -9.64019642987737$$
$$x_{24} = -56.5843132552156$$
$$x_{25} = 34.6144143855739$$
$$x_{26} = 12.7165564923597$$
$$x_{27} = -53.444832327677$$
$$x_{28} = 31.4783874220183$$
$$x_{29} = 84.8464312618769$$
$$x_{30} = -34.6160755605069$$
$$x_{31} = -66.0039687440156$$
$$x_{32} = -97.4100070356532$$
$$x_{33} = 91.1280108750695$$
$$x_{34} = -69.1441658996248$$
$$x_{35} = 22.0794939571531$$
$$x_{36} = -94.2691053608966$$
$$x_{37} = 9.61989414525743$$
$$x_{38} = -3.70016832822322$$
$$x_{39} = 87.9871925938327$$
$$x_{40} = 47.1658239901862$$
$$x_{41} = -40.8901810705869$$
$$x_{42} = 40.8889889691312$$
$$x_{43} = 59.7234578682196$$
$$x_{44} = 56.5836897166246$$
$$x_{45} = 53.444133531179$$
$$x_{46} = 81.7057333981014$$
$$x_{47} = 69.1437480697611$$
$$x_{48} = 15.8298315748782$$
$$x_{49} = 18.9520130189604$$
$$x_{50} = 50.3048284778932$$
$$x_{51} = 75.4245595332952$$
$$x_{52} = 94.2688804495667$$
$$x_{53} = 28.3435626361769$$
$$x_{54} = -87.9874507409867$$
$$x_{55} = 37.7513500111658$$
$$x_{56} = -84.8467088588013$$
$$x_{57} = -28.3460342726732$$
$$x_{58} = 3.59583707263255$$
$$x_{59} = -72.2844850005113$$
$$x_{60} = -75.4249107406798$$
$$x_{61} = 97.4097963860341$$
$$x_{62} = -62.8639119133944$$
$$x_{63} = -50.3056170075141$$
$$x_{64} = 72.2841026475956$$
$$x_{65} = -12.7284877901053$$
$$x_{66} = -18.9574918855266$$

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
$$\left[97.4097963860341, \infty\right)$$
Convexa en los intervalos
$$\left(-\infty, -100.550952067693\right]$$
Asíntotas horizontales
Hallemos las asíntotas horizontales mediante los límites de esta función con x->+oo y x->-oo
$$\lim_{x \to -\infty}\left(\left(2 x + 1\right) \sin{\left(x \right)}\right) = \left\langle -\infty, \infty\right\rangle$$
Tomamos como el límite
es decir,
ecuación de la asíntota horizontal a la izquierda:
$$y = \left\langle -\infty, \infty\right\rangle$$
$$\lim_{x \to \infty}\left(\left(2 x + 1\right) \sin{\left(x \right)}\right) = \left\langle -\infty, \infty\right\rangle$$
Tomamos como el límite
es decir,
ecuación de la asíntota horizontal a la derecha:
$$y = \left\langle -\infty, \infty\right\rangle$$
Asíntotas inclinadas
Se puede hallar la asíntota inclinada calculando el límite de la función (2*x + 1)*sin(x), dividida por x con x->+oo y x ->-oo
$$\lim_{x \to -\infty}\left(\frac{\left(2 x + 1\right) \sin{\left(x \right)}}{x}\right) = \left\langle -2, 2\right\rangle$$
Tomamos como el límite
es decir,
ecuación de la asíntota inclinada a la izquierda:
$$y = \left\langle -2, 2\right\rangle x$$
$$\lim_{x \to \infty}\left(\frac{\left(2 x + 1\right) \sin{\left(x \right)}}{x}\right) = \left\langle -2, 2\right\rangle$$
Tomamos como el límite
es decir,
ecuación de la asíntota inclinada a la derecha:
$$y = \left\langle -2, 2\right\rangle x$$
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:
$$\left(2 x + 1\right) \sin{\left(x \right)} = - \left(1 - 2 x\right) \sin{\left(x \right)}$$
- No
$$\left(2 x + 1\right) \sin{\left(x \right)} = \left(1 - 2 x\right) \sin{\left(x \right)}$$
- No
es decir, función
no es
par ni impar