(1 + tan θ + sec θ) (1 + cot θ − cosec θ) =
To find: (1 + tan θ + sec θ) (1 + cot θ − cosec θ)
Consider (1 + tan θ + sec θ) (1 + cot θ − cosec θ)
[∵ (a – b) (a + b) = a2 – b2]
[∵ sin2 θ + cos2 θ = 1]