limx→1(1-x)^(cosxπ/2)求极限lim(2/π arctanx)^x 其中x趋向于正无穷大

问题描述:

limx→1(1-x)^(cosxπ/2)求极限lim(2/π arctanx)^x 其中x趋向于正无穷大

lim (1-x)^(cosxπ/2)x→1 =lim (1-x)^[sin(1-x)π/2] (令y=1-x)x→1=lim y^[sin(yπ/2)]y→0=lim e^{[sin(yπ/2)]lny}y→0=lim e^(yπ/2*lny)y→0=lim e^[π/2*lny/(1/y)]y→0=[e^(π/2)]^lim lny/(1/y) (∞/∞,罗...