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प्रश्न
Prove that sin 75° – sin 15° = cos 105° + cos 15°
उत्तर
R.H.S = cos 105° + cos 15°
= cos(90° + 15°) + cos(90° – 75°)
= – sin 15° + sin 75°
= sin 75° – sin 15°
= L.H.S
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