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Popular >

3-2cos^2(x)=4sin^2(x)

Solución

3 - 2 cos^{2} (x) = 4 sin^{2} (x)

Solución

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

Grados

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

Pasos de solución

3 - 2 cos^{2} (x) = 4 sin^{2} (x)

Restar

4 sin^{2} (x)

de ambos lados

3 - 2 cos^{2} (x) - 4 sin^{2} (x) = 0

Re-escribir usando identidades trigonométricas

3 - 2 cos^{2} (x) - 4 sin^{2} (x)

Utilizar la identidad pitagórica:

cos^{2} (x) + sin^{2} (x) = 1

cos^{2} (x) = 1 - sin^{2} (x)

= 3 - 2 (1 - sin^{2} (x)) - 4 sin^{2} (x)

Simplificar

3 - 2 (1 - sin^{2} (x)) - 4 sin^{2} (x) : - 2 sin^{2} (x) + 1

3 - 2 (1 - sin^{2} (x)) - 4 sin^{2} (x)

Expandir

- 2 (1 - sin^{2} (x)) : - 2 + 2 sin^{2} (x)

- 2 (1 - sin^{2} (x))

Poner los parentesis utilizando:

a (b - c) = ab - a c

a = - 2, b = 1, c = sin^{2} (x)

= - 2 \cdot 1 - (- 2) sin^{2} (x)

Aplicar las reglas de los signos

- (- a) = a

= - 2 \cdot 1 + 2 sin^{2} (x)

Multiplicar los numeros:

2 \cdot 1 = 2

= - 2 + 2 sin^{2} (x)

= 3 - 2 + 2 sin^{2} (x) - 4 sin^{2} (x)

Simplificar

3 - 2 + 2 sin^{2} (x) - 4 sin^{2} (x) : - 2 sin^{2} (x) + 1

3 - 2 + 2 sin^{2} (x) - 4 sin^{2} (x)

Sumar elementos similares:

2 sin^{2} (x) - 4 sin^{2} (x) = - 2 sin^{2} (x)

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

Restar:

3 - 2 = 1

= - 2 sin^{2} (x) + 1

= - 2 sin^{2} (x) + 1

= - 2 sin^{2} (x) + 1

1 - 2 sin^{2} (x) = 0

Usando el método de sustitución

1 - 2 sin^{2} (x) = 0

Sea:

sin (x) = u

1 - 2 u^{2} = 0

1 - 2 u^{2} = 0 : u = \frac{1}{2}, u = - \frac{1}{2}

1 - 2 u^{2} = 0

Mover

1

al lado derecho

1 - 2 u^{2} = 0

Restar

1

de ambos lados

1 - 2 u^{2} - 1 = 0 - 1

Simplificar

- 2 u^{2} = - 1

- 2 u^{2} = - 1

Dividir ambos lados entre

- 2

- 2 u^{2} = - 1

Dividir ambos lados entre

- 2

\frac{- 2 u ^{2}}{- 2} = \frac{- 1}{- 2}

Simplificar

u^{2} = \frac{1}{2}

u^{2} = \frac{1}{2}

Para

x^{2} = f (a)

las soluciones son

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

u = \frac{1}{2}, u = - \frac{1}{2}

Sustituir en la ecuación

u = sin (x)

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

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

sin (x) = \frac{1}{2} : x = \frac{π}{4} + 2 πn, x = \frac{3 π}{4} + 2 πn

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

Soluciones generales para

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

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} sin (x) 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 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} sin (x) 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2}

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

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

sin (x) = - \frac{1}{2} : x = \frac{5 π}{4} + 2 πn, x = \frac{7 π}{4} + 2 πn

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

Soluciones generales para

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

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} sin (x) 0 \frac{1}{2} \frac{2}{2} \frac{3}{2} 1 \frac{3}{2} \frac{2}{2} \frac{1}{2} 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} sin (x) 0 - \frac{1}{2} - \frac{2}{2} - \frac{3}{2} - 1 - \frac{3}{2} - \frac{2}{2} - \frac{1}{2}

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

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

Combinar toda las soluciones

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

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sin^2(x)+sin(x)=-cos^2(x)

sin^{2} (x) + sin (x) = - cos^{2} (x)

arctan(x)=arccos(3/4)

arctan (x) = arccos (\frac{3}{4})

tan^2(θ)+7tan(θ)+9=0

tan^{2} (θ) + 7 tan (θ) + 9 = 0