What is the general solution for sin(x)cos(2x)+cos(x)sin(2x)=0 ?

The general solution for sin(x)cos(2x)+cos(x)sin(2x)=0 is x=(2pin)/3 ,x= pi/3+(2pin)/3

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

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

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

Degrees

x = 0^{\circ} + 12 0^{\circ} n, x = 6 0^{\circ} + 12 0^{\circ} n

Solution steps

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

Rewrite using trig identities

sin (x) cos (2 x) + cos (x) sin (2 x)

Use the Angle Sum identity:

sin (s) cos (t) + cos (s) sin (t) = sin (s + t)

= sin (x + 2 x)

sin (x + 2 x) = 0

General solutions for

sin (x + 2 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 + 2 x = 0 + 2 πn, x + 2 x = π + 2 πn

x + 2 x = 0 + 2 πn, x + 2 x = π + 2 πn

Solve

x + 2 x = 0 + 2 πn : x = \frac{2 πn}{3}

x + 2 x = 0 + 2 πn

Add similar elements:

x + 2 x = 3 x

3 x = 0 + 2 πn

0 + 2 πn = 2 πn

3 x = 2 πn

Divide both sides by

3

3 x = 2 πn

Divide both sides by

3

\frac{3 x}{3} = \frac{2 πn}{3}

Simplify

x = \frac{2 πn}{3}

x = \frac{2 πn}{3}

Solve

x + 2 x = π + 2 πn : x = \frac{π}{3} + \frac{2 πn}{3}

x + 2 x = π + 2 πn

Add similar elements:

x + 2 x = 3 x

3 x = π + 2 πn

Divide both sides by

3

3 x = π + 2 πn

Divide both sides by

3

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

Simplify

x = \frac{π}{3} + \frac{2 πn}{3}

x = \frac{π}{3} + \frac{2 πn}{3}

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

7 cos (5 x) + 9 = 12

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

3 cot (2 x) = - 1

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

cos (θ) = 3

What is the general solution for sin(x)cos(2x)+cos(x)sin(2x)=0 ?
The general solution for sin(x)cos(2x)+cos(x)sin(2x)=0 is x=(2pin)/3 ,x= pi/3+(2pin)/3