First of all,we need to understand that:
theta(θ)
(sin90°-θ)=cosθ
(cos90°-θ)=sinθ
tanθ=sinθ/cosθ
1/tanθ=cosθ/sinθ
cosθ^2+sinθ^2=1
In this case:
sin(90°-θ) × cos(90°-θ)/tanθ
=cosθ × sinθ × cosθ/sinθ
=cosθ × cosθ
=cos^2 θ
=1-sin^2 θ
Therefore, we can see that:
sin(90°-θ) × cos(90°-θ)/tanθ = 1-sin^2θ
Hope it helps!