Find the value of 3(sec2A - 1)(cosec A - 1)(cosec A + 1) + 4(cosec2A - cot2A).
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 7.
We know,
sec2A - 1 = tan2A
cosec2A - 1 = cot2A
Now,
⇒ 3(sec2A - 1)(cosec A - 1)(cosec A + 1) + 4(cosec2A - cot2A)
⇒ 3(tan2A)(cosec2A - 1) + 4(1)
⇒ 3 × tan2A × cot2A + 4
⇒ 3 + 4 = 7