Q. 12 C3.5( 4 Votes )

If tan 3 θ =cot (θ +18o), where 3 θ and θ +18o are acute angles, find the value of θ.

Answer :

tan 3θ = cot (θ + 18°) …(i)

We know that


tan θ = cot (90° - θ)


So, Eq. (i) become


Cot (90° - 3θ) = cot (θ + 18°)


On Equating both the sides, we get


90° - 3θ = θ + 18°


-3θ - θ = 18° -90°


-4θ = -72°


θ = 18°


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