Given the function f (x) = x-ax ^ 3 (a > 0), G (x) = SiNx, when x belongs to 0 to half of π, G (x) greater than or equal to f (x) is constant, the range of a is obtained

Given the function f (x) = x-ax ^ 3 (a > 0), G (x) = SiNx, when x belongs to 0 to half of π, G (x) greater than or equal to f (x) is constant, the range of a is obtained

∵ g (x) min ≥ f (x) maxg '(x) = cosx ∵ G' (x) = cosx ≥ 0 in X ∈ [0, π / 2]; G (x) = SiNx in X ∈ [0, π / 2]; G (x) min = g (0) = 0f '(x) = 1-3ax & # 178;, X ∈ [0, π / 2] ∵ Δ = 0-4