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cos^2x+cos^2y=0,25 la ecuación

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Solución numérica:

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Solución

Ha introducido [src]
   2         2         
cos (x) + cos (y) = 1/4
$$\cos^{2}{\left(x \right)} + \cos^{2}{\left(y \right)} = \frac{1}{4}$$
Solución detallada
Tenemos la ecuación
$$\cos^{2}{\left(x \right)} + \cos^{2}{\left(y \right)} = \frac{1}{4}$$
cambiamos
$$\cos^{2}{\left(x \right)} + \cos^{2}{\left(y \right)} - \frac{1}{4} = 0$$
$$- \sin^{2}{\left(x \right)} + \cos^{2}{\left(y \right)} + \frac{3}{4} = 0$$
Sustituimos
$$w = \sin{\left(x \right)}$$
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
$$a = -1$$
$$b = 0$$
$$c = \cos^{2}{\left(y \right)} + \frac{3}{4}$$
, entonces
D = b^2 - 4 * a * c = 

(0)^2 - 4 * (-1) * (3/4 + cos(y)^2) = 3 + 4*cos(y)^2

La ecuación tiene dos raíces.
w1 = (-b + sqrt(D)) / (2*a)

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

o
$$w_{1} = - \frac{\sqrt{4 \cos^{2}{\left(y \right)} + 3}}{2}$$
$$w_{2} = \frac{\sqrt{4 \cos^{2}{\left(y \right)} + 3}}{2}$$
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:
$$x_{1} = 2 \pi n + \operatorname{asin}{\left(w_{1} \right)}$$
$$x_{1} = 2 \pi n + \operatorname{asin}{\left(- \frac{\sqrt{4 \cos^{2}{\left(y \right)} + 3}}{2} \right)}$$
$$x_{1} = 2 \pi n - \operatorname{asin}{\left(\frac{\sqrt{4 \cos^{2}{\left(y \right)} + 3}}{2} \right)}$$
$$x_{2} = 2 \pi n + \operatorname{asin}{\left(w_{2} \right)}$$
$$x_{2} = 2 \pi n + \operatorname{asin}{\left(\frac{\sqrt{4 \cos^{2}{\left(y \right)} + 3}}{2} \right)}$$
$$x_{2} = 2 \pi n + \operatorname{asin}{\left(\frac{\sqrt{4 \cos^{2}{\left(y \right)} + 3}}{2} \right)}$$
$$x_{3} = 2 \pi n - \operatorname{asin}{\left(w_{1} \right)} + \pi$$
$$x_{3} = 2 \pi n - \operatorname{asin}{\left(- \frac{\sqrt{4 \cos^{2}{\left(y \right)} + 3}}{2} \right)} + \pi$$
$$x_{3} = 2 \pi n + \operatorname{asin}{\left(\frac{\sqrt{4 \cos^{2}{\left(y \right)} + 3}}{2} \right)} + \pi$$
$$x_{4} = 2 \pi n - \operatorname{asin}{\left(w_{2} \right)} + \pi$$
$$x_{4} = 2 \pi n - \operatorname{asin}{\left(\frac{\sqrt{4 \cos^{2}{\left(y \right)} + 3}}{2} \right)} + \pi$$
$$x_{4} = 2 \pi n - \operatorname{asin}{\left(\frac{\sqrt{4 \cos^{2}{\left(y \right)} + 3}}{2} \right)} + \pi$$
Gráfica
Respuesta rápida [src]
         /    /   _________________________________ \\              /    /   _________________________________ \\
         |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||              |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||
x1 = - re|acos|-------------------------------------|| + 2*pi - I*im|acos|-------------------------------------||
         \    \                  2                  //              \    \                  2                  //
$$x_{1} = - \operatorname{re}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + 2 \pi$$
         /    /  _________________________________\\              /    /  _________________________________\\
         |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||              |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||
x2 = - re|acos|-----------------------------------|| + 2*pi - I*im|acos|-----------------------------------||
         \    \                 2                 //              \    \                 2                 //
$$x_{2} = - \operatorname{re}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + 2 \pi$$
         /    /   _________________________________ \\     /    /   _________________________________ \\
         |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||     |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||
x3 = I*im|acos|-------------------------------------|| + re|acos|-------------------------------------||
         \    \                  2                  //     \    \                  2                  //
$$x_{3} = \operatorname{re}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)}$$
         /    /  _________________________________\\     /    /  _________________________________\\
         |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||     |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||
x4 = I*im|acos|-----------------------------------|| + re|acos|-----------------------------------||
         \    \                 2                 //     \    \                 2                 //
$$x_{4} = \operatorname{re}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)}$$
x4 = re(acos(sqrt(-(2*cos(y) - 1)*(2*cos(y) + 1))/2)) + i*im(acos(sqrt(-(2*cos(y) - 1)*(2*cos(y) + 1))/2))
Suma y producto de raíces [src]
suma
    /    /   _________________________________ \\              /    /   _________________________________ \\       /    /  _________________________________\\              /    /  _________________________________\\       /    /   _________________________________ \\     /    /   _________________________________ \\       /    /  _________________________________\\     /    /  _________________________________\\
    |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||              |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||       |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||              |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||       |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||     |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||       |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||     |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||
- re|acos|-------------------------------------|| + 2*pi - I*im|acos|-------------------------------------|| + - re|acos|-----------------------------------|| + 2*pi - I*im|acos|-----------------------------------|| + I*im|acos|-------------------------------------|| + re|acos|-------------------------------------|| + I*im|acos|-----------------------------------|| + re|acos|-----------------------------------||
    \    \                  2                  //              \    \                  2                  //       \    \                 2                 //              \    \                 2                 //       \    \                  2                  //     \    \                  2                  //       \    \                 2                 //     \    \                 2                 //
$$\left(\left(\left(- \operatorname{re}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + 2 \pi\right) + \left(- \operatorname{re}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + 2 \pi\right)\right) + \left(\operatorname{re}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)}\right)\right) + \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)}\right)$$
=
4*pi
$$4 \pi$$
producto
/    /    /   _________________________________ \\              /    /   _________________________________ \\\ /    /    /  _________________________________\\              /    /  _________________________________\\\ /    /    /   _________________________________ \\     /    /   _________________________________ \\\ /    /    /  _________________________________\\     /    /  _________________________________\\\
|    |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||              |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||| |    |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||              |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||| |    |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||     |    |-\/ -(1 + 2*cos(y))*(-1 + 2*cos(y))  ||| |    |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) ||     |    |\/ -(1 + 2*cos(y))*(-1 + 2*cos(y)) |||
|- re|acos|-------------------------------------|| + 2*pi - I*im|acos|-------------------------------------|||*|- re|acos|-----------------------------------|| + 2*pi - I*im|acos|-----------------------------------|||*|I*im|acos|-------------------------------------|| + re|acos|-------------------------------------|||*|I*im|acos|-----------------------------------|| + re|acos|-----------------------------------|||
\    \    \                  2                  //              \    \                  2                  /// \    \    \                 2                 //              \    \                 2                 /// \    \    \                  2                  //     \    \                  2                  /// \    \    \                 2                 //     \    \                 2                 ///
$$\left(- \operatorname{re}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + 2 \pi\right) \left(- \operatorname{re}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + 2 \pi\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(- \frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\sqrt{- \left(2 \cos{\left(y \right)} - 1\right) \left(2 \cos{\left(y \right)} + 1\right)}}{2} \right)}\right)}\right)$$
=
/    /    /   _______________\\     /    /   _______________\\\ /    /    /    _______________ \\     /    /    _______________ \\\ /            /    /   _______________\\     /    /   _______________\\\ /            /    /    _______________ \\     /    /    _______________ \\\
|    |    |  /          2    ||     |    |  /          2    ||| |    |    |   /          2     ||     |    |   /          2     ||| |            |    |  /          2    ||     |    |  /          2    ||| |            |    |   /          2     ||     |    |   /          2     |||
|    |    |\/  1 - 4*cos (y) ||     |    |\/  1 - 4*cos (y) ||| |    |    |-\/  1 - 4*cos (y)  ||     |    |-\/  1 - 4*cos (y)  ||| |            |    |\/  1 - 4*cos (y) ||     |    |\/  1 - 4*cos (y) ||| |            |    |-\/  1 - 4*cos (y)  ||     |    |-\/  1 - 4*cos (y)  |||
|I*im|acos|------------------|| + re|acos|------------------|||*|I*im|acos|--------------------|| + re|acos|--------------------|||*|-2*pi + I*im|acos|------------------|| + re|acos|------------------|||*|-2*pi + I*im|acos|--------------------|| + re|acos|--------------------|||
\    \    \        2         //     \    \        2         /// \    \    \         2          //     \    \         2          /// \            \    \        2         //     \    \        2         /// \            \    \         2          //     \    \         2          ///
$$\left(\operatorname{re}{\left(\operatorname{acos}{\left(- \frac{\sqrt{1 - 4 \cos^{2}{\left(y \right)}}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(- \frac{\sqrt{1 - 4 \cos^{2}{\left(y \right)}}}{2} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{\sqrt{1 - 4 \cos^{2}{\left(y \right)}}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\sqrt{1 - 4 \cos^{2}{\left(y \right)}}}{2} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(- \frac{\sqrt{1 - 4 \cos^{2}{\left(y \right)}}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(- \frac{\sqrt{1 - 4 \cos^{2}{\left(y \right)}}}{2} \right)}\right)} - 2 \pi\right) \left(\operatorname{re}{\left(\operatorname{acos}{\left(\frac{\sqrt{1 - 4 \cos^{2}{\left(y \right)}}}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{acos}{\left(\frac{\sqrt{1 - 4 \cos^{2}{\left(y \right)}}}{2} \right)}\right)} - 2 \pi\right)$$
(i*im(acos(sqrt(1 - 4*cos(y)^2)/2)) + re(acos(sqrt(1 - 4*cos(y)^2)/2)))*(i*im(acos(-sqrt(1 - 4*cos(y)^2)/2)) + re(acos(-sqrt(1 - 4*cos(y)^2)/2)))*(-2*pi + i*im(acos(sqrt(1 - 4*cos(y)^2)/2)) + re(acos(sqrt(1 - 4*cos(y)^2)/2)))*(-2*pi + i*im(acos(-sqrt(1 - 4*cos(y)^2)/2)) + re(acos(-sqrt(1 - 4*cos(y)^2)/2)))