lim(x->0)((x-arcsinx)/(tanx)^3)=lim(x->0)((x-arcsinx)/x³=lim(x->0)((1-1/√1-x²)/3x²=lim(x->0)((√1-x²-1)/3x²√1-x²=1/3lim(x->0)((√1-x²-1)/x²=1/3lim(x->0)(-x
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