lim (x-2/x+2)^x+2 x→∞ 请问这题求极限是怎样解,

Lim [x^2/(x^2-1)]^x (x→∞) lim(1+x/x)2x (x→∞) lim(x→0)e^x-x-1/x^2 lim x→1 x-1/x^2-x lim(x→0)[e^x-e^(2x)]/x lim xsin(2/x) x→∞ lim(1-x)^(2/x) x->0 lim(x(sin)^2) lim(x)lim(x→∞) [(x-1)/(x+1)]^2x 为什么 lim(x->∞) {[(-2)/(x+1)]*2x} = -4 lim x→∞ (x+sin 2x)/2 lim(x→0)(cosx-cos^2x)/x^2 lim(x→∞)(1-2/x)^2x x/2-1lim(1-2/x)x→∞ lim(x→0) (3x^2-5x+2), lim (x^3-x^2+4x)/(x^2+x) x→ 0 lim(x→1)(x^3-3x+2)/(x^3-x^2-x+1) 极限lim(x→0)(1-2/x)^x lim(x→0)(1-2x)^1/x 极限?