(3)设当x→0时, ^x-(a(x)^2+bx+1) 是比 x^2 高阶的无穷小,则 ()-|||-(A) =dfrac (1)(2) ,b=1 (B) a=1 =1-|||-(C) =-dfrac (1)(2) ,b=-1 (D) a=-1 =1

设当x→0时， e^x-(ax^2+bx+1)是比x2高阶的无穷小，则（）A. a=1/2 ,b=1B. a=1,b=1C. a=-1/2 ,b=-1D. a=

当x→0时 (x)=x-sin ax 与 (x)=(x)^2ln (1-bx) 是等价无穷小,-|||-则 ()-|||-(A) =1, =-dfrac (1)

例1.6 当x→0时, ((3+2tan x))^x-(3)^x 是 (sin )^2x+(x)^3cos dfrac (1)(x) 的 () .-|||-(A

1.当x→0时, (x)=(e)^x-dfrac (1+ax)(1+bx) 为x的三阶无穷小,则a,b分别为 __-|||-(A)1,0; (B) 1/2, 0

9.当x→0时, (x)=a(x)^3+bx 与 (x)=(int )_(0)^sin x((e)^(t^2)-1)dt 是等价无穷小,则 ()-|||-(A)

当x→1时，无穷小1-x和(1) 1-x^3;(-|||-(2) dfrac (1)(2)(1-(x)^2)是否同阶？是否等价？当x→1时，无穷小1-x和是否同

(B) dfrac (1)(2)(X)_(1)+dfrac (1)(2)(X)_(2)-|||-(C) dfrac (1)(2)(X)_(1)+dfrac (1

67.设当x→∞时，(1)/(ax^2)+bx+c是比(1)/(x+1)高阶的无穷小，求常数a、b、c的值.67.设当x→∞时，$\frac{1}{ax^{2}

6.设 (x,y)=dfrac (x-{y)^2+(y)^3}(2x+{y)^2}, 则,lim h(x,y)等于 ()-|||-(A) dfrac (1)(2

3、设 (x,y)=arctan dfrac (x)(y), 则 (1,1)=-|||-(A)1; (B)0; (C) dfrac {1)(2),dfrac