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sqrt(cos(x)^2-cos(x))/5-1=0 la ecuación

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Solución numérica:

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Solución

Ha introducido [src]
   __________________        
  /    2                     
\/  cos (x) - cos(x)         
--------------------- - 1 = 0
          5                  
$$\frac{\sqrt{\cos^{2}{\left(x \right)} - \cos{\left(x \right)}}}{5} - 1 = 0$$
Solución detallada
Tenemos la ecuación
$$\frac{\sqrt{\cos^{2}{\left(x \right)} - \cos{\left(x \right)}}}{5} - 1 = 0$$
cambiamos
$$\frac{\sqrt{\left(\cos{\left(x \right)} - 1\right) \cos{\left(x \right)}}}{5} - 1 = 0$$
$$\frac{\sqrt{\cos^{2}{\left(x \right)} - \cos{\left(x \right)}}}{5} - 1 = 0$$
Sustituimos
$$w = \cos{\left(x \right)}$$
$$\frac{\sqrt{w^{2} - w}}{5} = 1$$
Elevemos las dos partes de la ecuación a la potencia 2
$$\frac{w^{2}}{25} - \frac{w}{25} = 1$$
$$\frac{w^{2}}{25} - \frac{w}{25} = 1$$
Transpongamos la parte derecha de la ecuación miembro izquierdo de la ecuación con el signo negativo
$$\frac{w^{2}}{25} - \frac{w}{25} - 1 = 0$$
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
$$a = \frac{1}{25}$$
$$b = - \frac{1}{25}$$
$$c = -1$$
, entonces
D = b^2 - 4 * a * c = 

(-1/25)^2 - 4 * (1/25) * (-1) = 101/625

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

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

o
$$w_{1} = \frac{1}{2} + \frac{\sqrt{101}}{2}$$
$$w_{2} = \frac{1}{2} - \frac{\sqrt{101}}{2}$$

Como
$$\sqrt{w^{2} - w} = 5$$
y
$$\sqrt{w^{2} - w} \geq 0$$
entonces
$$5 \geq 0$$
Entonces la respuesta definitiva es:
$$w_{1} = \frac{1}{2} + \frac{\sqrt{101}}{2}$$
$$w_{2} = \frac{1}{2} - \frac{\sqrt{101}}{2}$$
hacemos cambio inverso
$$\cos{\left(x \right)} = w$$
Tenemos la ecuación
$$\cos{\left(x \right)} = w$$
es la ecuación trigonométrica más simple
Esta ecuación se reorganiza en
$$x = \pi n + \operatorname{acos}{\left(w \right)}$$
$$x = \pi n + \operatorname{acos}{\left(w \right)} - \pi$$
O
$$x = \pi n + \operatorname{acos}{\left(w \right)}$$
$$x = \pi n + \operatorname{acos}{\left(w \right)} - \pi$$
, donde n es cualquier número entero
sustituimos w:
$$x_{1} = \pi n + \operatorname{acos}{\left(w_{1} \right)}$$
$$x_{1} = \pi n + \operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}$$
$$x_{1} = \pi n + \operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}$$
$$x_{2} = \pi n + \operatorname{acos}{\left(w_{2} \right)}$$
$$x_{2} = \pi n + \operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}$$
$$x_{2} = \pi n + \operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}$$
$$x_{3} = \pi n + \operatorname{acos}{\left(w_{1} \right)} - \pi$$
$$x_{3} = \pi n - \pi + \operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}$$
$$x_{3} = \pi n - \pi + \operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}$$
$$x_{4} = \pi n + \operatorname{acos}{\left(w_{2} \right)} - \pi$$
$$x_{4} = \pi n - \pi + \operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}$$
$$x_{4} = \pi n - \pi + \operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}$$
Gráfica
Suma y producto de raíces [src]
suma
    /    /      _____\\              /    /      _____\\              /    /      _____\\       /    /      _____\\     /    /      _____\\       /    /      _____\\     /    /      _____\\
    |    |1   \/ 101 ||              |    |1   \/ 101 ||              |    |1   \/ 101 ||       |    |1   \/ 101 ||     |    |1   \/ 101 ||       |    |1   \/ 101 ||     |    |1   \/ 101 ||
- re|acos|- - -------|| + 2*pi - I*im|acos|- - -------|| + 2*pi - I*im|acos|- + -------|| + I*im|acos|- - -------|| + re|acos|- - -------|| + I*im|acos|- + -------|| + re|acos|- + -------||
    \    \2      2   //              \    \2      2   //              \    \2      2   //       \    \2      2   //     \    \2      2   //       \    \2      2   //     \    \2      2   //
$$\left(\left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)}\right) + \left(\left(2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)}\right) + \left(- \operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)} + 2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)}\right)\right)\right) + \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)}\right)$$
=
         /    /      _____\\
         |    |1   \/ 101 ||
4*pi + re|acos|- + -------||
         \    \2      2   //
$$\operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)} + 4 \pi$$
producto
/    /    /      _____\\              /    /      _____\\\ /           /    /      _____\\\ /    /    /      _____\\     /    /      _____\\\ /    /    /      _____\\     /    /      _____\\\
|    |    |1   \/ 101 ||              |    |1   \/ 101 ||| |           |    |1   \/ 101 ||| |    |    |1   \/ 101 ||     |    |1   \/ 101 ||| |    |    |1   \/ 101 ||     |    |1   \/ 101 |||
|- re|acos|- - -------|| + 2*pi - I*im|acos|- - -------|||*|2*pi - I*im|acos|- + -------|||*|I*im|acos|- - -------|| + re|acos|- - -------|||*|I*im|acos|- + -------|| + re|acos|- + -------|||
\    \    \2      2   //              \    \2      2   /// \           \    \2      2   /// \    \    \2      2   //     \    \2      2   /// \    \    \2      2   //     \    \2      2   ///
$$\left(2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)}\right) \left(- \operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)} + 2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)}\right)$$
=
 /           /    /      _____\\\ /    /    /      _____\\     /    /      _____\\\ /    /    /      _____\\     /    /      _____\\\ /            /    /      _____\\     /    /      _____\\\
 |           |    |1   \/ 101 ||| |    |    |1   \/ 101 ||     |    |1   \/ 101 ||| |    |    |1   \/ 101 ||     |    |1   \/ 101 ||| |            |    |1   \/ 101 ||     |    |1   \/ 101 |||
-|2*pi - I*im|acos|- + -------|||*|I*im|acos|- + -------|| + re|acos|- + -------|||*|I*im|acos|- - -------|| + re|acos|- - -------|||*|-2*pi + I*im|acos|- - -------|| + re|acos|- - -------|||
 \           \    \2      2   /// \    \    \2      2   //     \    \2      2   /// \    \    \2      2   //     \    \2      2   /// \            \    \2      2   //     \    \2      2   ///
$$- \left(2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)}\right) \left(- 2 \pi + \operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)}\right)$$
-(2*pi - i*im(acos(1/2 + sqrt(101)/2)))*(i*im(acos(1/2 + sqrt(101)/2)) + re(acos(1/2 + sqrt(101)/2)))*(i*im(acos(1/2 - sqrt(101)/2)) + re(acos(1/2 - sqrt(101)/2)))*(-2*pi + i*im(acos(1/2 - sqrt(101)/2)) + re(acos(1/2 - sqrt(101)/2)))
Respuesta rápida [src]
         /    /      _____\\              /    /      _____\\
         |    |1   \/ 101 ||              |    |1   \/ 101 ||
x1 = - re|acos|- - -------|| + 2*pi - I*im|acos|- - -------||
         \    \2      2   //              \    \2      2   //
$$x_{1} = - \operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)} + 2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)}$$
                /    /      _____\\
                |    |1   \/ 101 ||
x2 = 2*pi - I*im|acos|- + -------||
                \    \2      2   //
$$x_{2} = 2 \pi - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)}$$
         /    /      _____\\     /    /      _____\\
         |    |1   \/ 101 ||     |    |1   \/ 101 ||
x3 = I*im|acos|- - -------|| + re|acos|- - -------||
         \    \2      2   //     \    \2      2   //
$$x_{3} = \operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} - \frac{\sqrt{101}}{2} \right)}\right)}$$
         /    /      _____\\     /    /      _____\\
         |    |1   \/ 101 ||     |    |1   \/ 101 ||
x4 = I*im|acos|- + -------|| + re|acos|- + -------||
         \    \2      2   //     \    \2      2   //
$$x_{4} = \operatorname{re}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{1}{2} + \frac{\sqrt{101}}{2} \right)}\right)}$$
x4 = re(acos(1/2 + sqrt(101)/2)) + i*im(acos(1/2 + sqrt(101)/2))
Respuesta numérica [src]
x1 = -21.9911485751286 + 2.19031114446532*i
x2 = -84.8230016469244 + 2.19031114446532*i
x3 = 59.6902604182061 + 2.19031114446532*i
x4 = 94.2477796076938 + 2.3941266607411*i
x5 = 15.707963267949 + 2.19031114446532*i
x6 = -3.14159265358979 + 2.19031114446532*i
x7 = 34.5575191894877 - 2.19031114446532*i
x8 = -97.3893722612836 - 2.19031114446532*i
x9 = -43.9822971502571 + 2.3941266607411*i
x10 = 12.5663706143592 - 2.3941266607411*i
x11 = -53.4070751110265 - 2.19031114446532*i
x12 = -28.2743338823081 + 2.19031114446532*i
x13 = -9.42477796076938 - 2.19031114446532*i
x14 = -37.6991118430775 + 2.3941266607411*i
x15 = 75.398223686155 - 2.3941266607411*i
x16 = 50.2654824574367 - 2.3941266607411*i
x17 = -81.6814089933346 + 2.3941266607411*i
x18 = 6.28318530717959 + 2.3941266607411*i
x19 = 72.2566310325652 + 2.19031114446532*i
x20 = 25.1327412287183 + 2.3941266607411*i
x21 = 31.4159265358979 - 2.3941266607411*i
x22 = 25.1327412287183 - 2.3941266607411*i
x23 = -62.8318530717959 + 2.3941266607411*i
x24 = -84.8230016469244 - 2.19031114446532*i
x25 = -72.2566310325652 + 2.19031114446532*i
x26 = 78.5398163397448 - 2.19031114446532*i
x27 = 50.2654824574367 + 2.3941266607411*i
x27 = 50.2654824574367 + 2.3941266607411*i