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प्रश्न
Without using trigonometric tables, prove that:
sin35° sin55° − cos35° cos55° = 0
उत्तर
LHS=sin35° sin55°−cos35° cos55°
=sin35° cos(90°−55°)−cos35° sin(90−55°)
=sin35° cos35°−cos35° sin35°
=0
=RHS
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