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प्रश्न
Find the value of the following:
cos2 15° – sin2 15°
उत्तर
cos2 15° – sin2 15°
[∵ cos 2A = cos2 A – sin2 A, Here A = 15°]
= cos (2 × 15°)
= cos 30°
`= sqrt3/2`
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