lim(x→∞)(7x^3+4x)/(2x^3-x^2+3)=?

1.4求极限lim(x→∞) (x^2+x)/ (x^4-3x^+1) lim(x→∞)(x^2+x)/(x^4-3x-1)的极限 求lim(x→0)x cos 1/x lim(x→∞)x^2/ (3x-1)的极限 求极限：1.lim(x→∞) (3x^2 -2)/(x^4 +x^2 -1) 2.lim(x→∞) (4x^4 -2x^ 求极限lim(x→2)(x^2-3x+2)/(x^2+4x-12) 求极限lim (3x^3+5x^2+x) / (7x^3+5x-4) lim 3x^2-3x+2／x^2-4 求极限x→∞ lim(x→∞)（根号4x²-3x+2）/2x等于多少? 求极限 lim [(3+x)/(6+x)]^[(x-1)/2]= x→∞ 求极限 （（sin(x^3+x^2-x)+sin x) /x x→0 已知lim sinx/x=1 求极限值,limx→（x^2-1/x-1）和lim x→∞（2x^3-3x^2+4/5x^3+x-7)谢谢! 求解sin(x)+lim(x→-∞)+2/x*[x,(x+2)*3]/x+x6+x2/(x+[x,x2+2x])+√x