（π分之2arctanx）的x次方求极限 x趋向于正无穷

f(x) = [ 2arctanx / π ] ^ x ,ln f(x) = x * [ ln(2/π) + ln arctanx ]lim(x->+∞) ln f(x) = lim(x->+∞) [ ln(2/π) + ln arctanx ] / (1/x) o/o,洛必达法则= lim(x->+∞) (1/arctanx) * 1/(1+x²) / (-1/x...