4 [1 – sin2θ] [1 + tan2θ] = ___.
4
1
2
0
We know that (1 - sin2θ = cos2θ and 1 + tan2θ = sec2θ)
4 [1 – sin2θ] [1 + tan2θ] = 4 cos2θ×sec2θ=4
Because sec θ = 1cos θ
Solve: 4[1–sin2θ][1+tan2θ]
Simplify : 4(1 – sin2θ) (1 + tan2θ)