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If θ be acute angle and tan (4θ – 50°) = cot(50° – θ), then the value of θ in degrees is :
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- 20
- 50
- 40
- 30
Correct Option: D
tan (4θ – 50°) = cot (50° – θ)
⇒ tan (4θ – 50°)
= tan (90° – (50° – θ))
⇒ 4θ – 50° = 90° – (50° – θ)
⇒ 4θ – 50° = 90° – 50° + θ
⇒ 4θ – 50° = 40° + θ
⇒ 4θ – θ = 40° + 50°
| ⇒ 3θ = 90° ⇒ θ = | = 30° | 3 |
