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प्रश्न
If `1 - cos^2θ = 1/4`, then θ = ?
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उत्तर
`1 - cos^2θ = 1/4` ...[Given]
∴ `sin^2θ = 1/4` ...`[(∵ sin^2θ + cos^2θ = 1),(∴ 1 - cos^2θ = sin^2θ)]`
∴ `sin θ = 1/2` ...[Taking square root of both sides]
∴ θ = 30° ...`[∵ sin 30^circ = 1/2]`
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