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Solve each of the following for the given domain. State your answers by using the
indicated units. a. cos 𝜃 =−√3/2, −180° ≤ 𝜃 ≤ 360°
To solve for 𝜃, we need to find the angles in the given domain where cos 𝜃 = -√3/2.
Since cos 𝜃 = -√3/2 is negative, we are dealing with angles in the second and third quadrants where cosine is negative.
First, let's find the reference angle whose cosine is √3/2. We know that cos 30° = √3/2, so the reference angle is 30°.
In the second quadrant, cos 𝜃 = -√3/2, so 𝜃 = 180° - 30° = 150°.
In the third quadrant, cos 𝜃 = -√3/2, so 𝜃 = 180° + 30° = 210°.
Therefore, the solutions in the given domain are 𝜃 = 150° and 𝜃 = 210°.