The value of (tan29° cot61° - cosec²61°) + (cot²54°- sec²36°) + (sin²1° + sin²3° + sin²5° + ...+ sin²89°) is ?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 ie 20.5
= (tan29° cot61° - cosec²61°) + (cot²54°- sec²36°)+(sin²1° + sin²3° + sin²5° + ...+ sin²89°)
= (cot²61° - cosec²61°) + cot²54°- cosec²54° + (sin²1° + sin²3° + sin²5° + ...+ sin²89°)
= -1 - 1 + 22 + sin²45°
= -2 + 22 + (1/2)
= 20 + (1/2)
= 20.5