Answer:  2 - 2*sin³(θ) - √1 -sin²(θ)
Step-by-step explanation: Â In the expression
cos(theta)*sin2(theta) − cos(theta)
sin (2θ) = 2 sin(θ)*cos(θ)   ⇒  cos(θ)*2sin(θ)cos(θ) - cos(θ)
2cos²(θ)sin(θ) - cos(θ)      if we use cos²(θ) = 1-sin²(θ)
2 [ (1 - sin²(θ))*sin(θ)] - cos(θ)
2  - 2sin²(θ)sin(θ) - cos(θ)  ⇒  2-2sin³(θ)-cos(θ)  ;  cos(θ) = √1 -sin²(θ)
2 - 2*sin³(θ) - √1 -sin²(θ)