Questions: Find all the angles θ in [0°, 360°) that have a sin(θ) = -√2/2.
Transcript text: Find all the angles $\theta$ in $\left[0^{\circ}, 360^{\circ}\right)$ that have a $\sin (\theta)=\frac{-\sqrt{2}}{2}$.
Solution
Solution Steps
To find all the angles \(\theta\) in the interval \([0^\circ, 360^\circ)\) that have \(\sin(\theta) = \frac{-\sqrt{2}}{2}\), we need to identify the angles where the sine function takes this value. The sine function is negative in the third and fourth quadrants. The reference angle for \(\frac{\sqrt{2}}{2}\) is \(45^\circ\). Therefore, the angles in the specified interval are \(225^\circ\) and \(315^\circ\).
Step 1: Identify the Given Value
We are given the equation \( \sin(\theta) = \frac{-\sqrt{2}}{2} \).
Step 2: Determine the Reference Angle
The reference angle corresponding to \( \frac{\sqrt{2}}{2} \) is \( 45^\circ \).
Step 3: Identify the Quadrants
The sine function is negative in the third and fourth quadrants. Therefore, we need to find the angles in these quadrants.
Step 4: Calculate the Angles
Using the reference angle:
In the third quadrant:
\[
\theta_1 = 180^\circ + 45^\circ = 225^\circ
\]
In the fourth quadrant:
\[
\theta_2 = 360^\circ - 45^\circ = 315^\circ
\]
Final Answer
The angles \( \theta \) in the interval \([0^\circ, 360^\circ)\) that satisfy \( \sin(\theta) = \frac{-\sqrt{2}}{2} \) are
\[
\boxed{225^\circ, 315^\circ}
\]