Q. 75.0( 1 Vote )

If 0 < θ < 90, θ, sinθ = cos30, then obtain the value of 2tan2θ — 1.

Answer :

cos(90–θ ) = sinθ

tan(90–θ ) = cotθ


sin(90–θ ) = cosθ


cot(90–θ ) = tanθ


cosec(90–θ ) = secθ


sec(90–θ) = cosecθ


sinθ = cos30



θ = 60


Now, 2tan2θ – 1


= 2tan260 – 1


= 2(√3)2 – 1


= 5


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