Question

cos 38° · cos 52° - sin 38° · sin 52° =

• A. 1
• B. 0
• C. 2
• D. \( \frac{1}{2} \)

Hint:

Use the cosine addition formula to simplify expressions involving trigonometric functions of sum angles.

Answer 1

The Correct Option is B

Step 1: Use the cosine addition formula: \[ \cos(A + B) = \cos A \cdot \cos B - \sin A \cdot \sin B \] Step 2: Substituting \( A = 38^\circ \) and \( B = 52^\circ \), we get: \[ \cos(38^\circ + 52^\circ) = \cos 90^\circ = 0 \] Thus, the correct answer is \( \boxed{0} \).