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  1. 2 cosec² 23° cot² 67° – sin² 23° – sin² 67° – cot² 67° is equal to
    1. 1
    2. sec² 23°
    3. tan² 23°
    4. 0
Correct Option: B

2 cosec² 23° × cot² 67° - sin² 23° - sin² 67° - cot² 67°
= 2 . cosec² (90° - 67°) × cot² 67° - sin² 23° – sin² (90° – 23°) – cot² 67°
= 2 sec² 67° × cot² 67° – sin² 23° – cos² 23° – cot² 67°
= 2 cosec² 67° – 1 – cot² 67°
= cosec² 67° – 1 + cosec² 67° – cot² 67°
= cosec² 67° = sec² 23°



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