log(2)x^2-log(1/2)(x)-2=0 la ecuación
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Solución
Solución detallada
Abramos la expresión en la ecuación
( x 2 log ( 2 ) − x log ( 1 2 ) ) − 2 = 0 \left(x^{2} \log{\left(2 \right)} - x \log{\left(\frac{1}{2} \right)}\right) - 2 = 0 ( x 2 log ( 2 ) − x log ( 2 1 ) ) − 2 = 0 Obtenemos la ecuación cuadrática
x 2 log ( 2 ) + x log ( 2 ) − 2 = 0 x^{2} \log{\left(2 \right)} + x \log{\left(2 \right)} - 2 = 0 x 2 log ( 2 ) + x log ( 2 ) − 2 = 0 Es la ecuación de la forma
a*x^2 + b*x + c = 0 La ecuación cuadrática puede ser resuelta
con la ayuda del discriminante.
Las raíces de la ecuación cuadrática:
x 1 = D − b 2 a x_{1} = \frac{\sqrt{D} - b}{2 a} x 1 = 2 a D − b x 2 = − D − b 2 a x_{2} = \frac{- \sqrt{D} - b}{2 a} x 2 = 2 a − D − b donde D = b^2 - 4*a*c es el discriminante.
Como
a = log ( 2 ) a = \log{\left(2 \right)} a = log ( 2 ) b = log ( 2 ) b = \log{\left(2 \right)} b = log ( 2 ) c = − 2 c = -2 c = − 2 , entonces
D = b^2 - 4 * a * c = (log(2))^2 - 4 * (log(2)) * (-2) = log(2)^2 + 8*log(2) Como D > 0 la ecuación tiene dos raíces.
x1 = (-b + sqrt(D)) / (2*a) x2 = (-b - sqrt(D)) / (2*a) o
x 1 = − log ( 2 ) + log ( 2 ) 2 + 8 log ( 2 ) 2 log ( 2 ) x_{1} = \frac{- \log{\left(2 \right)} + \sqrt{\log{\left(2 \right)}^{2} + 8 \log{\left(2 \right)}}}{2 \log{\left(2 \right)}} x 1 = 2 log ( 2 ) − log ( 2 ) + log ( 2 ) 2 + 8 log ( 2 ) x 2 = − log ( 2 ) 2 + 8 log ( 2 ) − log ( 2 ) 2 log ( 2 ) x_{2} = \frac{- \sqrt{\log{\left(2 \right)}^{2} + 8 \log{\left(2 \right)}} - \log{\left(2 \right)}}{2 \log{\left(2 \right)}} x 2 = 2 log ( 2 ) − log ( 2 ) 2 + 8 log ( 2 ) − log ( 2 )
Teorema de Cardano-Vieta
reescribamos la ecuación
( x 2 log ( 2 ) − x log ( 1 2 ) ) − 2 = 0 \left(x^{2} \log{\left(2 \right)} - x \log{\left(\frac{1}{2} \right)}\right) - 2 = 0 ( x 2 log ( 2 ) − x log ( 2 1 ) ) − 2 = 0 de
a x 2 + b x + c = 0 a x^{2} + b x + c = 0 a x 2 + b x + c = 0 como ecuación cuadrática reducida
x 2 + b x a + c a = 0 x^{2} + \frac{b x}{a} + \frac{c}{a} = 0 x 2 + a b x + a c = 0 x 2 log ( 2 ) + x log ( 2 ) − 2 log ( 2 ) = 0 \frac{x^{2} \log{\left(2 \right)} + x \log{\left(2 \right)} - 2}{\log{\left(2 \right)}} = 0 log ( 2 ) x 2 log ( 2 ) + x log ( 2 ) − 2 = 0 p x + q + x 2 = 0 p x + q + x^{2} = 0 p x + q + x 2 = 0 donde
p = b a p = \frac{b}{a} p = a b p = − log ( 1 2 ) log ( 2 ) p = - \frac{\log{\left(\frac{1}{2} \right)}}{\log{\left(2 \right)}} p = − log ( 2 ) log ( 2 1 ) q = c a q = \frac{c}{a} q = a c q = − 2 log ( 2 ) q = - \frac{2}{\log{\left(2 \right)}} q = − log ( 2 ) 2 Fórmulas de Cardano-Vieta
x 1 + x 2 = − p x_{1} + x_{2} = - p x 1 + x 2 = − p x 1 x 2 = q x_{1} x_{2} = q x 1 x 2 = q x 1 + x 2 = log ( 1 2 ) log ( 2 ) x_{1} + x_{2} = \frac{\log{\left(\frac{1}{2} \right)}}{\log{\left(2 \right)}} x 1 + x 2 = log ( 2 ) log ( 2 1 ) x 1 x 2 = − 2 log ( 2 ) x_{1} x_{2} = - \frac{2}{\log{\left(2 \right)}} x 1 x 2 = − log ( 2 ) 2
____________
1 \/ 8 + log(2)
x1 = - - + --------------
2 ________
2*\/ log(2)
x 1 = − 1 2 + log ( 2 ) + 8 2 log ( 2 ) x_{1} = - \frac{1}{2} + \frac{\sqrt{\log{\left(2 \right)} + 8}}{2 \sqrt{\log{\left(2 \right)}}} x 1 = − 2 1 + 2 log ( 2 ) log ( 2 ) + 8
____________
1 \/ 8 + log(2)
x2 = - - - --------------
2 ________
2*\/ log(2)
x 2 = − log ( 2 ) + 8 2 log ( 2 ) − 1 2 x_{2} = - \frac{\sqrt{\log{\left(2 \right)} + 8}}{2 \sqrt{\log{\left(2 \right)}}} - \frac{1}{2} x 2 = − 2 log ( 2 ) log ( 2 ) + 8 − 2 1
x2 = -sqrt(log(2) + 8)/(2*sqrt(log(2))) - 1/2
Suma y producto de raíces
[src]
____________ ____________
1 \/ 8 + log(2) 1 \/ 8 + log(2)
- - + -------------- + - - - --------------
2 ________ 2 ________
2*\/ log(2) 2*\/ log(2)
( − log ( 2 ) + 8 2 log ( 2 ) − 1 2 ) + ( − 1 2 + log ( 2 ) + 8 2 log ( 2 ) ) \left(- \frac{\sqrt{\log{\left(2 \right)} + 8}}{2 \sqrt{\log{\left(2 \right)}}} - \frac{1}{2}\right) + \left(- \frac{1}{2} + \frac{\sqrt{\log{\left(2 \right)} + 8}}{2 \sqrt{\log{\left(2 \right)}}}\right) ( − 2 log ( 2 ) log ( 2 ) + 8 − 2 1 ) + ( − 2 1 + 2 log ( 2 ) log ( 2 ) + 8 )
/ ____________\ / ____________\
| 1 \/ 8 + log(2) | | 1 \/ 8 + log(2) |
|- - + --------------|*|- - - --------------|
| 2 ________ | | 2 ________ |
\ 2*\/ log(2) / \ 2*\/ log(2) /
( − 1 2 + log ( 2 ) + 8 2 log ( 2 ) ) ( − log ( 2 ) + 8 2 log ( 2 ) − 1 2 ) \left(- \frac{1}{2} + \frac{\sqrt{\log{\left(2 \right)} + 8}}{2 \sqrt{\log{\left(2 \right)}}}\right) \left(- \frac{\sqrt{\log{\left(2 \right)} + 8}}{2 \sqrt{\log{\left(2 \right)}}} - \frac{1}{2}\right) ( − 2 1 + 2 log ( 2 ) log ( 2 ) + 8 ) ( − 2 log ( 2 ) log ( 2 ) + 8 − 2 1 )
− 2 log ( 2 ) - \frac{2}{\log{\left(2 \right)}} − log ( 2 ) 2