lim(1-2^1/x)/(1+2^1/x)x→0+,等于-1,x→0-时等于1?

lim(1-x)^(2/x) x->0 极限：lim(x->2)1/(x-2) lim(1-(5/x))^x-2 lim(x+e^2x)^(1/sinx) X趋于0 Lim(xlnx)=Lim(lnx/(1/x))=Lim(1/x/(-1/x^2))=Lim(-x)=0Lim(lnx/(1/x))=Lim(1/x/(-1/x^2))其中这步使怎么转化的? (1) lim(x->正无穷) x-lnx (2) lim(x->0+) cosx^1/x^2 lim (e^x-sinx-1)/(arcsinx^2) lim 1/(x-2). 存在极限吗? lim(x->0)(2xsinx)/(secx-1) Lim(x>1) x-1/x^2+x-2.计算 lim x→1 x-1/x^2-x lim(x^2+1/x^2-2x)^x=? lim(x->无穷大){(2^x-3^x)/2}^(1/x) Lim [x^2/(x^2-1)]^x (x→∞) lim x->正无穷大 x ( sqrt(x^2+1)-x ) lim(x->0)((2-x)/(3-x))^1/x lim(1+x/x)2x (x→∞) lim(x→0)e^x-x-1/x^2