f'(x)＝2arcsinx×1/√(1-x^2) f''(x)＝2/(1-x^2)＋2xarcsinx/√(1-x^2)^3 f'''(x)＝4x/(1-x^2)^2＋2arcsinx/√(1-x^2)^3＋2x/(1-x^2)^2＋6xarcsinx/√(1-x^2)^5 f'''(0)＝0