设y=[(2/π)arctanx]^x则：lny=xln[(2/π)arctanx]=x[ln(2/π)+lnarctanx]lim[x→+∞] lny=lim[x→+∞] x[ln(2/π)+lnarctanx]=lim[x→+∞] [ln(2/π)+lnarctanx]/x⁻¹洛必达法则=lim[x→+∞] -{1/[(1+x&#...