If θ is a positive acute angle and tan2θ tan3θ = 1, then the value of θ is:
Show answer & explanation
Correct answer: A
Explanation
The correct answer is Option 1 i.e. 18o.
| Understanding/Application |
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tan2θ tan3θ = 1 sin2θ sin3θ/cos2θ cos3θ = 1 sin2θ sin3θ = cos2θ cos3θ cos2θ cos3θ - sin2θ sin3θ = 0 cos(2θ + 3θ) = 0 |
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cos5θ = 900 5θ = 90 θ = 180 |