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  1. If θ is an acute angle and tan θ + cot θ = 2, then the value of tan5 θ + cot5 θ is
    1. 1
    2. 2
    3. 3
    4. 4
Correct Option: B

tan θ + cot θ = 2

⇒ tan θ +
1
= 2
tan θ

tan² θ + 1
= 2
tan θ

⇒ tan² θ +1 = 2 tanθ
⇒ tan²θ – 2 tan θ + 1 = 0
⇒ (tan θ –1)² = 0
⇒ tanθ – 1= 0 ⇒ tanθ = 1
∴ cot θ =
1
= 1
tan θ

∴ tan5θ + cot5θ = 1 + 1 = 2



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