If tan (3A) = cot (A - 22°), where 3A is an acute angle, then what is the value of A?
- AOption (a)
25°
- BOption (b)
27°
- COption (c)
28°
- DOption (d)
30°
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Correct answer
28°
Why this answer is correct
Given:
tan(3A) = cot(A - 22°), where 3A is an acute angle,
Calculation:
cot(x) = tan(90° - x).
\(\tan(3A) = \tan\left(90^∘ - (A - 22^∘)\right)\)
\(\tan(3A) = \tan\left(90^∘ - A + 22^∘\right)\)
\(\tan(3A) = \tan(112^∘ - A)\)
Since the tangent function is periodic with a period of 180°, we have:
\(3A = 112^∘ - A + n \cdot 180^∘\)
where n is an integer. Since 3A is an acute angle, (i.e. (0∘ < A < 90∘).
3A = 112∘ - A
4A = 112∘
A = 28∘
∴ The correct answer is 28∘.



















