lim(3x^2+5)/(5x+3)*sin4/x x趋向于无穷的.咋做

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→0) (3x^2-5x+2), 数学难题,求指教~~极限到底是什么玩意我还不懂.1.lim（x^2-2x+6）2.lim(x^2-4)/(x-2）3.lim(x^2-6x=8)/(x^-5x=4)4.lim[1/(1-x)-1/(1-x^3)5.lim(sin2x)/x^26.lim(sin5x)/x7.lim(tan3x)/(sin7x)8.lim[(1+x)/x]^2x例如这道例题~lim[(1/3)x+1] 帮忙`````````一些求极限的数学题一.求极限1.lim 3x^+2x+1x→12.lim x^+3x+2/x的三次方+4x^+5x→03.lim x^-1/x-1x→14.lim x^-3x+2/1-x^x→15.lim sin2x/5xx→06.lim sin3x/tan2xx→07.lim (1+x)的x分之2次方x→08.lim （1+2/n)的n次 lim(1-5/x)∧(2x+3) 用罗必达法则解 （见图）lim [(e^x)-1/sin（5x)]x->0lim [1-cos(5x)/1-cos(7x)]x->0lim x->0 [(8^x-7^x-1)/(x^2)-1]lim [1-(6/x)]^x x->∞ lim 7cos(3x)sec(9x)x->pi/2 lim（x^2+2x-5）/（x^3+x+5）,x趋于无穷 lim(x→∞)[(X^2+2x+5)/(3x^2-x+1) = lim(x+5)(2x-1)/(x^2-3x-1)球极限,x无穷大 lim(2^x+3^x+5^x)^(1/x)x-->正无穷 lim(2^x+3^x+5^x)^(1/x)x-->正无穷 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 求极限lim(x→∞)(2x/3-x)-(2/3x)求极限lim(x→5)根号(x-1)-2/x-5 lim[x→1]f(x)存在,且f(x)=2x+5+3lim[x→1]f(x),求f(x) lim(x→∞)[5X*(tan2/3x)] lim(2x^-3x+1) x→∞ ^代表平方lim(x的3次方)/2x+1 x→∞lim(x的3次方+5x^)/（x-2)^ 再次拜谢 为什么lim(x^3-2x+5)/(3x^5+2x+3)=0 lim(2x^3+3x^2+5)/(7x^3+4x^2-1)