lim (x^2+1)/(2x^2+1) x→0为什么这一步等于1 不是还有个

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) 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>1) x-1/x^2+x-2.计算 lim x→1 x-1/x^2-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 lim(x+1/x+2)^x=?x趋于无穷 lim(x趋于无穷)(x/1+x)^(x+2)=? 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 1.lim x->∞ （2x/x^2+1)*cosx 2..lim x->∞{ [(x^2-x)arctanx]/x^3-x-5}3..lim x->0 （e^x-e^-x-2x)/(x-sinx) 4..lim x->0 (sinx-x)/(x^3) 5..lim x->0 (x^2*tanx)/(x-tanx) 6..lim x->0 (1+3/x)^2x 7..lim x->0 (1+2x)^(3/sinx) 8.lim x->∞ (x/1+x)^(x-3) 9..li