lim[1/(x+1)-3/(x^3+1)],x趋于-1 等于多少?为什么

lim（x-3/x+1）^x lim趋向无穷大 lim(x+e^3x)^1/x lim(1-x)^3/x 求极限~ lim x-1/x平方+3x-4 x-1 lim(x->0)((2-x)/(3-x))^1/x lim(x->无穷大){(2^x-3^x)/2}^(1/x) lim（ x→∞）（1+x / x)^3x 极限函数计算lim( x^3 / sinx - x )lim( (1/e^x-1)-(1/x) ) 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 lim(x趋近于1)x^3-1/x-1 lim(2x+3/2x+1)^(x+1) lim x->无限大 (1+1/2x) ^ 3x+lnx lim(2x-3/2x+1）^x+1 lim x-无穷 (√3x^2+1)/x+1 lim(x趋向于无穷)(1+3/x)^(x-3) lim(x→0)(1-3x)^(3/x) lim(1+3x)^3/x x趋向于0 计算lim(1+3x)^3/x x趋向0