tg^2(x)+ctg^2(x)+3*(tg(x)+ctg(x))+4=0 la ecuación
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Solución
Solución detallada
Tenemos la ecuación
( 3 ( tan ( x ) + cot ( x ) ) + ( tan 2 ( x ) + cot 2 ( x ) ) ) + 4 = 0 \left(3 \left(\tan{\left(x \right)} + \cot{\left(x \right)}\right) + \left(\tan^{2}{\left(x \right)} + \cot^{2}{\left(x \right)}\right)\right) + 4 = 0 ( 3 ( tan ( x ) + cot ( x ) ) + ( tan 2 ( x ) + cot 2 ( x ) ) ) + 4 = 0 cambiamos
tan 2 ( x ) + 3 tan ( x ) + cot 2 ( x ) + 3 cot ( x ) + 3 = 0 \tan^{2}{\left(x \right)} + 3 \tan{\left(x \right)} + \cot^{2}{\left(x \right)} + 3 \cot{\left(x \right)} + 3 = 0 tan 2 ( x ) + 3 tan ( x ) + cot 2 ( x ) + 3 cot ( x ) + 3 = 0 3 ( tan ( x ) + cot ( x ) ) + tan 2 ( x ) + cot 2 ( x ) + 3 = 0 3 \left(\tan{\left(x \right)} + \cot{\left(x \right)}\right) + \tan^{2}{\left(x \right)} + \cot^{2}{\left(x \right)} + 3 = 0 3 ( tan ( x ) + cot ( x ) ) + tan 2 ( x ) + cot 2 ( x ) + 3 = 0 Sustituimos
w = cot ( x ) w = \cot{\left(x \right)} w = cot ( x ) 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 = D − b 2 a w_{1} = \frac{\sqrt{D} - b}{2 a} w 1 = 2 a D − b w 2 = − D − b 2 a w_{2} = \frac{- \sqrt{D} - b}{2 a} w 2 = 2 a − D − b donde D = b^2 - 4*a*c es el discriminante.
Como
a = 1 a = 1 a = 1 b = 3 b = 3 b = 3 c = tan 2 ( x ) + 3 tan ( x ) + 3 c = \tan^{2}{\left(x \right)} + 3 \tan{\left(x \right)} + 3 c = tan 2 ( x ) + 3 tan ( x ) + 3 , entonces
D = b^2 - 4 * a * c = (3)^2 - 4 * (1) * (3 + tan(x)^2 + 3*tan(x)) = -3 - 12*tan(x) - 4*tan(x)^2 La ecuación tiene dos raíces.
w1 = (-b + sqrt(D)) / (2*a) w2 = (-b - sqrt(D)) / (2*a) o
w 1 = − 4 tan 2 ( x ) − 12 tan ( x ) − 3 2 − 3 2 w_{1} = \frac{\sqrt{- 4 \tan^{2}{\left(x \right)} - 12 \tan{\left(x \right)} - 3}}{2} - \frac{3}{2} w 1 = 2 − 4 tan 2 ( x ) − 12 tan ( x ) − 3 − 2 3 w 2 = − − 4 tan 2 ( x ) − 12 tan ( x ) − 3 2 − 3 2 w_{2} = - \frac{\sqrt{- 4 \tan^{2}{\left(x \right)} - 12 \tan{\left(x \right)} - 3}}{2} - \frac{3}{2} w 2 = − 2 − 4 tan 2 ( x ) − 12 tan ( x ) − 3 − 2 3 hacemos cambio inverso
cot ( x ) = w \cot{\left(x \right)} = w cot ( x ) = w sustituimos w:
Gráfica
0 -80 -60 -40 -20 20 40 60 80 -100 100 0 250000000000
Suma y producto de raíces
[src]
/ / ___\\ / / ___\\ / / ___\\ / / ___\\
pi | |1 I*\/ 3 || | |1 I*\/ 3 || | |1 I*\/ 3 || | |1 I*\/ 3 ||
- -- + - re|atan|- - -------|| - I*im|atan|- - -------|| + - re|atan|- + -------|| - I*im|atan|- + -------||
4 \ \2 2 // \ \2 2 // \ \2 2 // \ \2 2 //
( − re ( atan ( 1 2 + 3 i 2 ) ) − i im ( atan ( 1 2 + 3 i 2 ) ) ) + ( − π 4 + ( − re ( atan ( 1 2 − 3 i 2 ) ) − i im ( atan ( 1 2 − 3 i 2 ) ) ) ) \left(- \operatorname{re}{\left(\operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{3} i}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{3} i}{2} \right)}\right)}\right) + \left(- \frac{\pi}{4} + \left(- \operatorname{re}{\left(\operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{3} i}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{3} i}{2} \right)}\right)}\right)\right) ( − re ( atan ( 2 1 + 2 3 i ) ) − i im ( atan ( 2 1 + 2 3 i ) ) ) + ( − 4 π + ( − re ( atan ( 2 1 − 2 3 i ) ) − i im ( atan ( 2 1 − 2 3 i ) ) ) )
/ / ___\\ / / ___\\ / / ___\\ / / ___\\
| |1 I*\/ 3 || | |1 I*\/ 3 || pi | |1 I*\/ 3 || | |1 I*\/ 3 ||
- re|atan|- + -------|| - re|atan|- - -------|| - -- - I*im|atan|- + -------|| - I*im|atan|- - -------||
\ \2 2 // \ \2 2 // 4 \ \2 2 // \ \2 2 //
− re ( atan ( 1 2 + 3 i 2 ) ) − re ( atan ( 1 2 − 3 i 2 ) ) − π 4 − i im ( atan ( 1 2 + 3 i 2 ) ) − i im ( atan ( 1 2 − 3 i 2 ) ) - \operatorname{re}{\left(\operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{3} i}{2} \right)}\right)} - \operatorname{re}{\left(\operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{3} i}{2} \right)}\right)} - \frac{\pi}{4} - i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{3} i}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{3} i}{2} \right)}\right)} − re ( atan ( 2 1 + 2 3 i ) ) − re ( atan ( 2 1 − 2 3 i ) ) − 4 π − i im ( atan ( 2 1 + 2 3 i ) ) − i im ( atan ( 2 1 − 2 3 i ) )
/ / / ___\\ / / ___\\\ / / / ___\\ / / ___\\\
-pi | | |1 I*\/ 3 || | |1 I*\/ 3 ||| | | |1 I*\/ 3 || | |1 I*\/ 3 |||
----*|- re|atan|- - -------|| - I*im|atan|- - -------|||*|- re|atan|- + -------|| - I*im|atan|- + -------|||
4 \ \ \2 2 // \ \2 2 /// \ \ \2 2 // \ \2 2 ///
− π 4 ( − re ( atan ( 1 2 − 3 i 2 ) ) − i im ( atan ( 1 2 − 3 i 2 ) ) ) ( − re ( atan ( 1 2 + 3 i 2 ) ) − i im ( atan ( 1 2 + 3 i 2 ) ) ) - \frac{\pi}{4} \left(- \operatorname{re}{\left(\operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{3} i}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{3} i}{2} \right)}\right)}\right) \left(- \operatorname{re}{\left(\operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{3} i}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{3} i}{2} \right)}\right)}\right) − 4 π ( − re ( atan ( 2 1 − 2 3 i ) ) − i im ( atan ( 2 1 − 2 3 i ) ) ) ( − re ( atan ( 2 1 + 2 3 i ) ) − i im ( atan ( 2 1 + 2 3 i ) ) )
/ / / ___\\ / / ___\\\ / / / ___\\ / / ___\\\
| | |1 I*\/ 3 || | |1 I*\/ 3 ||| | | |1 I*\/ 3 || | |1 I*\/ 3 |||
-pi*|I*im|atan|- + -------|| + re|atan|- + -------|||*|I*im|atan|- - -------|| + re|atan|- - -------|||
\ \ \2 2 // \ \2 2 /// \ \ \2 2 // \ \2 2 ///
--------------------------------------------------------------------------------------------------------
4
− π ( re ( atan ( 1 2 − 3 i 2 ) ) + i im ( atan ( 1 2 − 3 i 2 ) ) ) ( re ( atan ( 1 2 + 3 i 2 ) ) + i im ( atan ( 1 2 + 3 i 2 ) ) ) 4 - \frac{\pi \left(\operatorname{re}{\left(\operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{3} i}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{3} i}{2} \right)}\right)}\right) \left(\operatorname{re}{\left(\operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{3} i}{2} \right)}\right)} + i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{3} i}{2} \right)}\right)}\right)}{4} − 4 π ( re ( atan ( 2 1 − 2 3 i ) ) + i im ( atan ( 2 1 − 2 3 i ) ) ) ( re ( atan ( 2 1 + 2 3 i ) ) + i im ( atan ( 2 1 + 2 3 i ) ) )
-pi*(i*im(atan(1/2 + i*sqrt(3)/2)) + re(atan(1/2 + i*sqrt(3)/2)))*(i*im(atan(1/2 - i*sqrt(3)/2)) + re(atan(1/2 - i*sqrt(3)/2)))/4
x 1 = − π 4 x_{1} = - \frac{\pi}{4} x 1 = − 4 π
/ / ___\\ / / ___\\
| |1 I*\/ 3 || | |1 I*\/ 3 ||
x2 = - re|atan|- - -------|| - I*im|atan|- - -------||
\ \2 2 // \ \2 2 //
x 2 = − re ( atan ( 1 2 − 3 i 2 ) ) − i im ( atan ( 1 2 − 3 i 2 ) ) x_{2} = - \operatorname{re}{\left(\operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{3} i}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{1}{2} - \frac{\sqrt{3} i}{2} \right)}\right)} x 2 = − re ( atan ( 2 1 − 2 3 i ) ) − i im ( atan ( 2 1 − 2 3 i ) )
/ / ___\\ / / ___\\
| |1 I*\/ 3 || | |1 I*\/ 3 ||
x3 = - re|atan|- + -------|| - I*im|atan|- + -------||
\ \2 2 // \ \2 2 //
x 3 = − re ( atan ( 1 2 + 3 i 2 ) ) − i im ( atan ( 1 2 + 3 i 2 ) ) x_{3} = - \operatorname{re}{\left(\operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{3} i}{2} \right)}\right)} - i \operatorname{im}{\left(\operatorname{atan}{\left(\frac{1}{2} + \frac{\sqrt{3} i}{2} \right)}\right)} x 3 = − re ( atan ( 2 1 + 2 3 i ) ) − i im ( atan ( 2 1 + 2 3 i ) )
x3 = -re(atan(1/2 + sqrt(3)*i/2)) - i*im(atan(1/2 + sqrt(3)*i/2))