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If tan α = √5 - 2, then the value of tan α - cot α is:
A-2
B√5 + 2
C2√5
D-4
Answer & Solution
Correct answer: D. -4
1. cot α = 1 / tan α = 1 / (√5 - 2).
2. Rationalise: 1/(√5 - 2) = (√5 + 2)/((√5)² - 2²) = (√5 + 2)/1 = √5 + 2.
3. tan α - cot α = (√5 - 2) - (√5 + 2) = -4.
_Source: RRB Group D CEN-02/2018 PYQ, Q.39._
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