What is the general solution for sin(2x)tan(x)=sin(x) ?

The general solution for sin(2x)tan(x)=sin(x) is x=2pin,x=pi+2pin,x= pi/6+2pin,x=(5pi)/6+2pin

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Popular >

sin(2x)tan(x)=sin(x)

Solution

sin (2 x) tan (x) = sin (x)

Solution

x = 2 πn, x = π + 2 πn, x = \frac{π}{6} + 2 πn, x = \frac{5 π}{6} + 2 πn

Degrees

x = 0^{\circ} + 36 0^{\circ} n, x = 18 0^{\circ} + 36 0^{\circ} n, x = 3 0^{\circ} + 36 0^{\circ} n, x = 15 0^{\circ} + 36 0^{\circ} n

Solution steps

sin (2 x) tan (x) = sin (x)

Subtract

sin (x)

from both sides

sin (2 x) tan (x) - sin (x) = 0

Rewrite using trig identities

- sin (x) + sin (2 x) tan (x)

Use the Double Angle identity:

sin (2 x) = 2 sin (x) cos (x)

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

- sin (x) + 2 cos (x) sin (x) tan (x) = 0

Factor

- sin (x) + 2 cos (x) sin (x) tan (x) : sin (x) (- 1 + 2 cos (x) tan (x))

- sin (x) + 2 cos (x) sin (x) tan (x)

Factor out common term

sin (x)

= sin (x) (- 1 + 2 cos (x) tan (x))

sin (x) (- 1 + 2 cos (x) tan (x)) = 0

Solving each part separately

sin (x) = 0 or - 1 + 2 cos (x) tan (x) = 0

sin (x) = 0 : x = 2 πn, x = π + 2 πn

sin (x) = 0

General solutions for

sin (x) = 0

sin (x)

periodicity table with

2 πn

cycle:

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 = 0 + 2 πn, x = π + 2 πn

x = 0 + 2 πn, x = π + 2 πn

Solve

x = 0 + 2 πn : x = 2 πn

x = 0 + 2 πn

0 + 2 πn = 2 πn

x = 2 πn

x = 2 πn, x = π + 2 πn

- 1 + 2 cos (x) tan (x) = 0 : x = \frac{π}{6} + 2 πn, x = \frac{5 π}{6} + 2 πn

- 1 + 2 cos (x) tan (x) = 0

Rewrite using trig identities

- 1 + 2 cos (x) tan (x)

cos (x) tan (x) = sin (x)

cos (x) tan (x)

Use the basic trigonometric identity:

tan (x) = \frac{sin ( x )}{cos ( x )}

= cos (x) \frac{sin ( x )}{cos ( x )}

Simplify

cos (x) \frac{sin ( x )}{cos ( x )} : sin (x)

cos (x) \frac{sin ( x )}{cos ( x )}

Multiply fractions:

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

= \frac{sin ( x ) cos ( x )}{cos ( x )}

Cancel the common factor:

cos (x)

= sin (x)

= sin (x)

= - 1 + 2 sin (x)

- 1 + 2 sin (x) = 0

Move

1

to the right side

- 1 + 2 sin (x) = 0

Add

1

to both sides

- 1 + 2 sin (x) + 1 = 0 + 1

Simplify

2 sin (x) = 1

2 sin (x) = 1

Divide both sides by

2

2 sin (x) = 1

Divide both sides by

2

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

Simplify

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

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

General solutions for

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

sin (x)

periodicity table with

2 πn

cycle:

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}{6} + 2 πn, x = \frac{5 π}{6} + 2 πn

x = \frac{π}{6} + 2 πn, x = \frac{5 π}{6} + 2 πn

Combine all the solutions

x = 2 πn, x = π + 2 πn, x = \frac{π}{6} + 2 πn, x = \frac{5 π}{6} + 2 πn

Popular Examples

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3 sin^{3} (x) = 0

tan(x)(tan(x)-3)+2=0

tan (x) (tan (x) - 3) + 2 = 0

sin(x)-4sin^3(x)=0

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

2sin(x)=3sqrt(3)

2 sin (x) = 33

sin^2(θ)= 1/9

sin^{2} (θ) = \frac{1}{9}

Frequently Asked Questions (FAQ)

What is the general solution for sin(2x)tan(x)=sin(x) ?
The general solution for sin(2x)tan(x)=sin(x) is x=2pin,x=pi+2pin,x= pi/6+2pin,x=(5pi)/6+2pin