Harshit Singh
Last Activity: 4 Years ago
Dear student
Option (C) is correct
Justification:
(1 + tan θ + sec θ) (1 + cot θ-cosec θ)
We know that,
tan θ = sin θ/cos θ
sec θ = 1/ cos θ
cot θ = cos θ/sin θ
cosec θ = 1/sin θ
Now, substitute the above values in the given problem,
we get
= (1+ sin θ/cos θ+ 1/cos θ) (1 + cos θ/sin θ-1/sin θ)
Simplify the above equation,
= (cos θ +sin θ+1)/cos θ × (sin θ+cos θ-1)/sin θ
= (cos θ+sin θ)^2 -1^2/(cos θ sin θ)
= (cos^2 θ + sin^2 θ + 2cos θ sin θ-1)/(cos θ sin θ)
= (1+ 2cos θ sin θ-1)/(cos θ sin θ)
(Since cos^2 θ + sin^2 θ = 1)
= (2cos θ sin θ)/(cos θ sin θ)
= 2
Therefore, (1 + tan θ + sec θ) (1 + cot θ-cosec θ) =2
Thanks