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Question
If cosθ = sin60° and θ is an acute angle find the value of 1- 2 sin2θ
Sum
Solution
cosθ = sin60°
⇒ cosθ = `sqrt(3)/(2)`
⇒ cosθ = cos30°
⇒ θ = 30°
Now,
1 - 2sin2θ
= 1 - 2sin230°
= `1 - 2(1/2)^2`
= `1 - 2 xx (1)/(4)`
= `1 - (1)/(2)`
= `(1)/(2)`.
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Trigonometric Equation Problem and Solution
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