lim (x->1) (x^2-6x+8)/(x^2-5x+4) 怎么算?

lim (x->1) (x^2-6x+8)/(x^2-5x+4) 怎么算? 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 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] lim(1-x)^(2/x) x->0 1、lim(x->无穷大) e^x arctanx2、lim(x->0)sinx√1+sin(1/x)3、lim(x->无穷大)【（√x^2+x+1）-【(√x^2-x+1)】4、lim(x->无穷大)((x+{x+(x)^0.5]^0.5}^0.5)/(2x+1)^0.55、lim(x->0)(sin3x+x^2sin1/x)/((1+cosx)x)6、lim(n->无穷大)(2^n)(si 求极限：1、lim(x→1) (3x² + 8x + 9) 2、lim (x->∞) (2x² - 6/x³ + 2) 几道大学微积分求极限的题1,lim(x→∞)｛(x-3)^12(2x+1)^8/(3x-1)^20｝2,lim(x→+∞)｛(3x³+5x²+4)/[(√x^6)+2]｝3,lim(x→∞)[x+³√(1-x³)]4,lim(x→1)｛[√(x+3)-2]/√x-1｝ lim(x^2+1/x^2-2x)^x=? Lim(x>1) x-1/x^2+x-2.计算 lim x→1 x-1/x^2-x lim(x->无穷大){(2^x-3^x)/2}^(1/x) Lim [x^2/(x^2-1)]^x (x→∞) lim x->正无穷大 x ( sqrt(x^2+1)-x ) lim(x->0)((2-x)/(3-x))^1/x lim(1+x/x)2x (x→∞) lim(x→0)e^x-x-1/x^2 lim(x+1/x+2)^x=?x趋于无穷 lim(x趋于无穷)(x/1+x)^(x+2)=?