Question: If sin (A – B) = 1/2, cos (A + B) = 1/2, and 0° < A + B ≤ 90°, A > B, then A =
Answer:
Given:
1. sin(A - B) = 1/2
2. cos(A + B) = 1/2
3. 0° < A + B ≤ 90° and A > B
Step-by-step solution:
1. Determine A - B:
sin(A - B) = 1/2
The angle whose sine is 1/2 is 30° or 150°. Since A > B, A - B must
be positive, so:
A
- B = 30°
2. Determine A + B:
cos(A + B) = 1/2
The angle whose cosine is 1/2 is 60° or 300°. Given the condition 0°
< A + B ≤ 90°, the valid angle is:
A
+ B = 60°
3. Solve the equations:
We
have two equations:
A
- B = 30°
A
+ B = 60°
Add these equations to find A:
(A
- B) + (A + B) = 30° + 60°
2A
= 90°
A
= 45°
Thus, A = 45°
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