sin(arccos√2/2)-2arcsin0

Compute step by step:

• Let θ = arccos(√2/2). Then cos θ = √2/2 and θ ∈ [0, π], so θ = π/4. Thus sin(arccos(√2/2)) = sin(π/4) = √2/2.
• arcsin(0) = 0, so -2 arcsin(0) = 0.

Total: √2/2. decimal ≈ 0.7071.