Questions: Solve the equation for exact solutions over the interval [0°, 360°).
2 sin 2 theta = -1
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. The solution set is .
(Type an integer or a decimal. Type your answer in degrees. Do not include the degree symbol in your answer. Use a comma to separate answers as needed.)
B. The solution is the empty set.
Transcript text: Solve the equation for exact solutions over the interval $\left[0^{\circ}, 360^{\circ}\right)$.
\[
2 \sin 2 \theta=-1
\]
Select the correct choice below and, if necessary, fill in the answer box to complete your choice.
A. The solution set is \{ $\square$ \}.
(Type an integer or a decimal. Type your answer in degrees. Do not include the degree symbol in your answer. Use a comma to separate answers as needed.)
B. The solution is the empty set.
Solution
Solution Steps
Step 1: Isolate the Sine Function
Starting with the equation:
\[
2 \sin 2\theta = -1
\]
we isolate the sine function:
\[
\sin 2\theta = -\frac{1}{2}
\]
Step 2: Determine Reference Angles
The reference angle for which \(\sin x = \frac{1}{2}\) is \(30^\circ\). Since the sine function is negative in the third and fourth quadrants, we find the angles:
\[
2\theta = 210^\circ \quad \text{and} \quad 2\theta = 330^\circ
\]
Step 3: Solve for \(\theta\)
Dividing both angles by 2 to solve for \(\theta\):
\[
\theta_1 = \frac{210^\circ}{2} = 105^\circ
\]
\[
\theta_2 = \frac{330^\circ}{2} = 165^\circ
\]