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प्रश्न
If the angle θ= –60º, find the value of cosθ.
उत्तर
We know that,
cos(-α) = cosα
∴ cos(-60°) = cos60°
∴ cos(-60°) = 1/2
∴ cos(-60°) = cosθ = 1/2
∴ cosθ = 1/2
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