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प्रश्न
Evaluate sin25° cos65° + cos25° sin65°
उत्तर
sin25° cos65° + cos25° sin65°
=(sin 25°) {cos(90°-25°)}+cos 25°{sin(90°-25)}
=(sin 25°)(sin 25°) + (cos 25°)(cos 25°)
= sin225° + cos225°
= 1 (As sin2A + cos2A = 1)
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