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sin(x)*(2*sin(x)-1)+sqrt(3)*sin(x)+sin(4*pi/3)=0 la ecuación

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Solución numérica:

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Solución

Ha introducido [src]
                          ___             /4*pi\    
sin(x)*(2*sin(x) - 1) + \/ 3 *sin(x) + sin|----| = 0
                                          \ 3  /    
$$\left(\left(2 \sin{\left(x \right)} - 1\right) \sin{\left(x \right)} + \sqrt{3} \sin{\left(x \right)}\right) + \sin{\left(\frac{4 \pi}{3} \right)} = 0$$
Solución detallada
Tenemos la ecuación
$$\left(\left(2 \sin{\left(x \right)} - 1\right) \sin{\left(x \right)} + \sqrt{3} \sin{\left(x \right)}\right) + \sin{\left(\frac{4 \pi}{3} \right)} = 0$$
cambiamos
$$2 \sin^{2}{\left(x \right)} - \sin{\left(x \right)} + \sqrt{3} \sin{\left(x \right)} - \frac{\sqrt{3}}{2} = 0$$
$$\left(\left(2 \sin{\left(x \right)} - 1\right) \sin{\left(x \right)} + \sqrt{3} \sin{\left(x \right)}\right) + \sin{\left(\frac{4 \pi}{3} \right)} = 0$$
Sustituimos
$$w = \sin{\left(x \right)}$$
Abramos la expresión en la ecuación
$$w \left(2 w - 1\right) + \sqrt{3} w - \frac{\sqrt{3}}{2} = 0$$
Obtenemos la ecuación cuadrática
$$2 w^{2} - w + \sqrt{3} w - \frac{\sqrt{3}}{2} = 0$$
Es la ecuación de la forma
a*w^2 + b*w + c = 0

La ecuación cuadrática puede ser resuelta
con la ayuda del discriminante.
Las raíces de la ecuación cuadrática:
$$w_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$w_{2} = \frac{- \sqrt{D} - b}{2 a}$$
donde D = b^2 - 4*a*c es el discriminante.
Como
$$a = 2$$
$$b = -1 + \sqrt{3}$$
$$c = - \frac{\sqrt{3}}{2}$$
, entonces
D = b^2 - 4 * a * c = 

(-1 + sqrt(3))^2 - 4 * (2) * (-sqrt(3)/2) = (-1 + sqrt(3))^2 + 4*sqrt(3)

Como D > 0 la ecuación tiene dos raíces.
w1 = (-b + sqrt(D)) / (2*a)

w2 = (-b - sqrt(D)) / (2*a)

o
$$w_{1} = - \frac{\sqrt{3}}{4} + \frac{1}{4} + \frac{\sqrt{\left(-1 + \sqrt{3}\right)^{2} + 4 \sqrt{3}}}{4}$$
$$w_{2} = - \frac{\sqrt{\left(-1 + \sqrt{3}\right)^{2} + 4 \sqrt{3}}}{4} - \frac{\sqrt{3}}{4} + \frac{1}{4}$$
hacemos cambio inverso
$$\sin{\left(x \right)} = w$$
Tenemos la ecuación
$$\sin{\left(x \right)} = w$$
es la ecuación trigonométrica más simple
Esta ecuación se reorganiza en
$$x = 2 \pi n + \operatorname{asin}{\left(w \right)}$$
$$x = 2 \pi n - \operatorname{asin}{\left(w \right)} + \pi$$
O
$$x = 2 \pi n + \operatorname{asin}{\left(w \right)}$$
$$x = 2 \pi n - \operatorname{asin}{\left(w \right)} + \pi$$
, donde n es cualquier número entero
sustituimos w:
$$x_{1} = 2 \pi n + \operatorname{asin}{\left(w_{1} \right)}$$
$$x_{1} = 2 \pi n + \operatorname{asin}{\left(- \frac{\sqrt{3}}{4} + \frac{1}{4} + \frac{\sqrt{\left(-1 + \sqrt{3}\right)^{2} + 4 \sqrt{3}}}{4} \right)}$$
$$x_{1} = 2 \pi n + \operatorname{asin}{\left(- \frac{\sqrt{3}}{4} + \frac{1}{4} + \frac{\sqrt{\left(-1 + \sqrt{3}\right)^{2} + 4 \sqrt{3}}}{4} \right)}$$
$$x_{2} = 2 \pi n + \operatorname{asin}{\left(w_{2} \right)}$$
$$x_{2} = 2 \pi n + \operatorname{asin}{\left(- \frac{\sqrt{\left(-1 + \sqrt{3}\right)^{2} + 4 \sqrt{3}}}{4} - \frac{\sqrt{3}}{4} + \frac{1}{4} \right)}$$
$$x_{2} = 2 \pi n - \operatorname{asin}{\left(- \frac{1}{4} + \frac{\sqrt{3}}{4} + \frac{\sqrt{\left(-1 + \sqrt{3}\right)^{2} + 4 \sqrt{3}}}{4} \right)}$$
$$x_{3} = 2 \pi n - \operatorname{asin}{\left(w_{1} \right)} + \pi$$
$$x_{3} = 2 \pi n - \operatorname{asin}{\left(- \frac{\sqrt{3}}{4} + \frac{1}{4} + \frac{\sqrt{\left(-1 + \sqrt{3}\right)^{2} + 4 \sqrt{3}}}{4} \right)} + \pi$$
$$x_{3} = 2 \pi n - \operatorname{asin}{\left(- \frac{\sqrt{3}}{4} + \frac{1}{4} + \frac{\sqrt{\left(-1 + \sqrt{3}\right)^{2} + 4 \sqrt{3}}}{4} \right)} + \pi$$
$$x_{4} = 2 \pi n - \operatorname{asin}{\left(w_{2} \right)} + \pi$$
$$x_{4} = 2 \pi n - \operatorname{asin}{\left(- \frac{\sqrt{\left(-1 + \sqrt{3}\right)^{2} + 4 \sqrt{3}}}{4} - \frac{\sqrt{3}}{4} + \frac{1}{4} \right)} + \pi$$
$$x_{4} = 2 \pi n + \operatorname{asin}{\left(- \frac{1}{4} + \frac{\sqrt{3}}{4} + \frac{\sqrt{\left(-1 + \sqrt{3}\right)^{2} + 4 \sqrt{3}}}{4} \right)} + \pi$$
Gráfica
Respuesta rápida [src]
     -pi 
x1 = ----
      3  
$$x_{1} = - \frac{\pi}{3}$$
     pi
x2 = --
     6 
$$x_{2} = \frac{\pi}{6}$$
     5*pi
x3 = ----
      6  
$$x_{3} = \frac{5 \pi}{6}$$
     4*pi
x4 = ----
      3  
$$x_{4} = \frac{4 \pi}{3}$$
x4 = 4*pi/3
Suma y producto de raíces [src]
suma
  pi   pi   5*pi   4*pi
- -- + -- + ---- + ----
  3    6     6      3  
$$\left(\left(- \frac{\pi}{3} + \frac{\pi}{6}\right) + \frac{5 \pi}{6}\right) + \frac{4 \pi}{3}$$
=
2*pi
$$2 \pi$$
producto
-pi  pi 5*pi 4*pi
----*--*----*----
 3   6   6    3  
$$\frac{4 \pi}{3} \frac{5 \pi}{6} \cdot - \frac{\pi}{3} \frac{\pi}{6}$$
=
     4
-5*pi 
------
  81  
$$- \frac{5 \pi^{4}}{81}$$
-5*pi^4/81
Respuesta numérica [src]
x1 = -39.7935069454707
x2 = 69.6386371545737
x3 = 25.6563400043166
x4 = -60.2138591938044
x5 = 4.18879020478639
x6 = 84.2994028713261
x7 = 54.4542726622231
x8 = 31.9395253114962
x9 = 24.0855436775217
x10 = 44.5058959258554
x11 = -91.6297857297023
x12 = 17.8023583703422
x13 = 11.5191730631626
x14 = -57.5958653158129
x15 = -49.7418836818384
x16 = 41.8879020478639
x17 = 2.61799387799149
x18 = 8.90117918517108
x19 = 61.7846555205993
x20 = -33.5103216382911
x21 = 27.7507351067098
x22 = -85.3466004225227
x23 = -79.0634151153431
x24 = -97.9129710368819
x25 = -18.3259571459405
x26 = -43.4586983746588
x27 = 86.9173967493176
x28 = -284.837733925475
x29 = 88.4881930761125
x30 = 16.7551608191456
x31 = -62.3082542961976
x32 = -9.94837673636768
x33 = 46.6002910282486
x34 = -5.75958653158129
x35 = -51.3126800086333
x36 = -100.007366139275
x37 = -135.612082879959
x38 = -26.1799387799149
x39 = -32.4631240870945
x40 = 52.8834763354282
x41 = 20140.2269033886
x42 = -87.4409955249159
x43 = 85.870199198121
x44 = -93.7241808320955
x45 = 60.7374579694027
x46 = -77.4926187885482
x47 = -46.0766922526503
x48 = 10.471975511966
x49 = 78.0162175641465
x50 = 82.2050077689329
x51 = -83.7758040957278
x52 = -13.6135681655558
x53 = -53.9306738866248
x54 = -19.8967534727354
x55 = 55.5014702134197
x56 = 63.3554518473942
x57 = 0.523598775598299
x58 = -16.2315620435473
x59 = -56.025068989018
x60 = 1298.52496348378
x61 = -63.8790506229925
x62 = -27.2271363311115
x63 = 30.3687289847013
x64 = 92.1533845053006
x65 = 74.3510261349584
x66 = 48.1710873550435
x67 = 75.9218224617533
x68 = -2.0943951023932
x69 = 99.4837673636768
x70 = -90.0589894029074
x71 = -35.081117965086
x72 = 19.3731546971371
x73 = -68.5914396033772
x74 = 71.733032256967
x75 = -12.0427718387609
x76 = -24.60914245312
x77 = 90.5825881785057
x78 = 98.4365698124802
x79 = -76.4454212373516
x80 = 38.2227106186758
x81 = 40.317105721069
x82 = 13.0899693899575
x83 = -41.3643032722656
x84 = 129.852496348378
x85 = -47.6474885794452
x86 = -3.66519142918809
x87 = -5022.35945553888
x88 = 96.8657734856853
x89 = 34.0339204138894
x90 = 68.0678408277789
x91 = -71.2094334813686
x92 = -70.162235930172
x92 = -70.162235930172