中四數學(三角)10分!!唔該急用

1
((1-sin^2θ)/sin^2θ)((1-cos^2θ)/cos^2θ)
=(cos^2θ)(sin^2θ)/(sin^2θ)(cos^2θ)
=1
2
1-sin θ cos θ tan θ
=1-sin θ cos θ (sin θ/cos θ)
=1-sin^2 θ
=cos^2 θ