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Prove that (sin 65° + cos 25°)(sin 65° − cos 25°) = 0. |
Answer» (sin 65° + cos 25°)(sin 65° − cos 25°) = 0 LHS = (sin 65° + cos 25°)(sin 65° − cos 25°) = sin2 65° – cos2 25° = sin2 65° – cos2 (90 – 65)° = sin2 65° – sin2 65° = 0 = RHS |
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