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Popular >

sec(x)=2cos(x)

Solución

sec (x) = 2 cos (x)

Solución

x = \frac{π}{4} + 2 πn, x = \frac{7 π}{4} + 2 πn, x = \frac{3 π}{4} + 2 πn, x = \frac{5 π}{4} + 2 πn

Grados

x = 4 5^{\circ} + 36 0^{\circ} n, x = 31 5^{\circ} + 36 0^{\circ} n, x = 13 5^{\circ} + 36 0^{\circ} n, x = 22 5^{\circ} + 36 0^{\circ} n

Pasos de solución

sec (x) = 2 cos (x)

Restar

2 cos (x)

de ambos lados

sec (x) - 2 cos (x) = 0

Re-escribir usando identidades trigonométricas

sec (x) - 2 cos (x)

Utilizar la identidad trigonométrica básica:

cos (x) = \frac{1}{sec ( x )}

= sec (x) - 2 \cdot \frac{1}{sec ( x )}

2 \cdot \frac{1}{sec ( x )} = \frac{2}{sec ( x )}

2 \cdot \frac{1}{sec ( x )}

Multiplicar fracciones:

a \cdot \frac{b}{c} = \frac{a \cdot b}{c}

= \frac{1 \cdot 2}{sec ( x )}

Multiplicar los numeros:

1 \cdot 2 = 2

= \frac{2}{sec ( x )}

= sec (x) - \frac{2}{sec ( x )}

- \frac{2}{sec ( x )} + sec (x) = 0

Usando el método de sustitución

- \frac{2}{sec ( x )} + sec (x) = 0

Sea:

sec (x) = u

- \frac{2}{u} + u = 0

- \frac{2}{u} + u = 0 : u = 2, u = - 2

- \frac{2}{u} + u = 0

Multiplicar ambos lados por

u

- \frac{2}{u} + u = 0

Multiplicar ambos lados por

u

- \frac{2}{u} u + uu = 0 \cdot u

Simplificar

- \frac{2}{u} u + uu = 0 \cdot u

Simplificar

- \frac{2}{u} u : - 2

- \frac{2}{u} u

Multiplicar fracciones:

a \cdot \frac{b}{c} = \frac{a \cdot b}{c}

= - \frac{2 u}{u}

Eliminar los terminos comunes:

u

= - 2

Simplificar

uu : u^{2}

uu

Aplicar las leyes de los exponentes:

a^{b} \cdot a^{c} = a^{b + c}

uu = u^{1 + 1}

= u^{1 + 1}

Sumar:

1 + 1 = 2

= u^{2}

Simplificar

0 \cdot u : 0

0 \cdot u

Aplicar la regla

0 \cdot a = 0

= 0

- 2 + u^{2} = 0

- 2 + u^{2} = 0

- 2 + u^{2} = 0

Resolver

- 2 + u^{2} = 0 : u = 2, u = - 2

- 2 + u^{2} = 0

Mover

2

al lado derecho

- 2 + u^{2} = 0

Sumar

2

a ambos lados

- 2 + u^{2} + 2 = 0 + 2

Simplificar

u^{2} = 2

u^{2} = 2

Para

x^{2} = f (a)

las soluciones son

x = f (a), - f (a)

u = 2, u = - 2

u = 2, u = - 2

Verificar las soluciones

Encontrar los puntos no definidos (singularidades):

u = 0

Tomar el(los) denominador(es) de

- \frac{2}{u} + u

y comparar con cero

u = 0

Los siguientes puntos no están definidos

u = 0

Combinar los puntos no definidos con las soluciones:

u = 2, u = - 2

Sustituir en la ecuación

u = sec (x)

sec (x) = 2, sec (x) = - 2

sec (x) = 2, sec (x) = - 2

sec (x) = 2 : x = \frac{π}{4} + 2 πn, x = \frac{7 π}{4} + 2 πn

sec (x) = 2

Soluciones generales para

sec (x) = 2

sec (x)

tabla de valores periódicos con

2 πn

intervalos:

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} sec (x) 1 \frac{2 3}{3} 22 Undefined - 2 - 2 - \frac{2 3}{3} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} sec (x) - 1 - \frac{2 3}{3} - 2 - 2 Undefined 22 \frac{2 3}{3}

x = \frac{π}{4} + 2 πn, x = \frac{7 π}{4} + 2 πn

x = \frac{π}{4} + 2 πn, x = \frac{7 π}{4} + 2 πn

sec (x) = - 2 : x = \frac{3 π}{4} + 2 πn, x = \frac{5 π}{4} + 2 πn

sec (x) = - 2

Soluciones generales para

sec (x) = - 2

sec (x)

tabla de valores periódicos con

2 πn

intervalos:

x 0 \frac{π}{6} \frac{π}{4} \frac{π}{3} \frac{π}{2} \frac{2 π}{3} \frac{3 π}{4} \frac{5 π}{6} sec (x) 1 \frac{2 3}{3} 22 Undefined - 2 - 2 - \frac{2 3}{3} x π \frac{7 π}{6} \frac{5 π}{4} \frac{4 π}{3} \frac{3 π}{2} \frac{5 π}{3} \frac{7 π}{4} \frac{11 π}{6} sec (x) - 1 - \frac{2 3}{3} - 2 - 2 Undefined 22 \frac{2 3}{3}

x = \frac{3 π}{4} + 2 πn, x = \frac{5 π}{4} + 2 πn

x = \frac{3 π}{4} + 2 πn, x = \frac{5 π}{4} + 2 πn

Combinar toda las soluciones

x = \frac{π}{4} + 2 πn, x = \frac{7 π}{4} + 2 πn, x = \frac{3 π}{4} + 2 πn, x = \frac{5 π}{4} + 2 πn

Ejemplos populares

sec(5 θ/4)=2,0<θ<2pi

sec (5 \frac{θ}{4}) = 2, 0 < θ < 2 π

2sin(x/2)=1

2 sin (\frac{x}{2}) = 1

sin^2(x)-3cos^2(x)=0

sin^{2} (x) - 3 cos^{2} (x) = 0

cos(2x+pi/3)=sin(3x)

cos (2 x + \frac{π}{3}) = sin (3 x)

solvefor y,x=arcsin(y)resolver para

y, x = arcsin (y)