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  1. The numerical value of 1 +
    1
    - sec² 27° +
    1
    - cosec² 27° is
    cot² 63°sin² 63°
    1. 1
    2. 2
    3. - 1
    4. 0
Correct Option: D

1 +
1
- sec²27° +
1
- cosec²27° = 1 + tan²63° - sec²27° + cosec²63° - cosec²27°
cot²63°sin²63°

= 1 + tan²(90° – 27°) – sec²27° + cosec2 (90° – 27°) – cosec²27°
= 1 + cot²27° – sec²27° + sec²27° – cose²27°
= 1 + cot²27° – cosec²27°
= 1 – 1 = 0
[∵ cosec²θ - cot²θ = 1]



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