lim(x→∞)(2x^3-x^2-3)/(x^3-x+1),请教一下高手,这一题怎么求啊?谢谢

lim x→∞(2x+1)/(3x-4) Lim(x→∞)((2x-3k)/2x)-2x= Lim(x→∞)xsin3/x, 求lim(x→0)x cos 1/x lim(x→∞)x^2/ (3x-1)的极限 ( x+3) lim (------------)的x次方 x->∞ ( x-2) lim(x→∞)(4x^3+2x-1)/(2x^3-3x+1) lim(x→∞)(2x^3-x^2-3)/(x^3-x+1) lim(x→∞)(7x^3+4x)/(2x^3-x^2+3)=? lim(x→∞)[(X^2+2x+5)/(3x^2-x+1) = lim(x→∞)[（x^3+x^2+x^1+1)^(1/3) - x] 的极限. lim(x→∞)(x^2+x)/(x^4-3x-1)的极限 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 求极限 lim [(3+x)/(6+x)]^[(x-1)/2]= x→∞求极限 lim [(3+x)/(6+x)]^[(x-1)/2]=x→∞ f(x)=(2+e^x)/1+e^2x)+ | x|sin1/x求 1)lim[x→+∞]f(x); 2)lim[x→-∞]f(x); 3)lim[x→∞]f(x) lim x→0 sin2x/sin5xlim x→0 (1-cos2x)/x²lim x→0 in(1-x/2)^1/xlim x→∞ (1+2/x)^2x+1lim x→0 sin2x/sin5xlim x→0 (1-cos2x)/x²lim x→0 in(1-x/2)^1/xlim x→∞ (1+2/x)^2x+1lim x→3 (x-3)cos1/(x-3)lim x→0 (e^sinx-e^x)/(sinx-x) lim(x→∞)(2x+3)=5. lim(x→0) (3x^2-5x+2), lim(x→0)2x^3-x+1 烦人的数学微积分1、lim(x→0)Sin3x/Sin2x2、lim(x→0)x/3*Sin3x3、lim(x→0)[Xsin(3/x)+(tanx/2x)]4、lim(x→3)Sin(x-3)/(X^2-X-6)5、lim(x→∞)[1+(1/2x)^x6、lim(x→∞)(x+3/x)^x7、lim(x→0)（1-x/2)^1/x+118、求下列函数的间断