Solve the trigonometric equation for .
Answer and explanation
Correct answer: B.
- Step 1: Isolate the cosine term: . For , the compound angle lies in the interval .
- Step 2: The reference angle is , and cosine is positive in the first and fourth quadrants: or . Dividing by 2 gives or .
Answer
.
Why not the others: The angles omit dividing by 2; the angles correspond to ; the angles fail to find the fourth-quadrant solution.
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