If tan (8θ – 11°) tan (11θ – 13°) = 1, then find the value of tan10θ + cot5θ ?
Sol:
We know, if tanA. tanB = 1
Then, A + B = 90°
Now,
Tan(8θ – 11) . tan (11θ – 13) = 1
∴ 8θ – 11 + 11θ – 13 = 90
⇒ 19θ = 114
⇒ θ = 6
Now,Tan10θ + cot 5θ
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