got lost and i need help

Question

Use a Double- or Half-Angle Formula to solve the equation in the interval [0, 2π). (Enter your answers as a comma-separated list. Round your answers to three decimal places where appropriate.)

sin 2θ + sin θ = 0

θ =

 

Answer 1

Step 1:

The trigonometric equation is .

Double-angle formula : .

Separate the solutions.

and .

Simplify and rewrite the equations.

and .

General solution for :

General solution :

If , then , where is an integer.

In the interval the general solution is

Solution :

The solution of the trigonometric equation is .