1.设 (x)=dfrac ({x)^2-x}(|x|({x)^2-1)} 则f(x)的可去间断点是 () .-|||-(A) =0; (B) =-1;-|||-(C) =1; (D) =2.

3.9 设函数 (x)=dfrac (sin (x-1))({x)^2-1}, 则 () .-|||-(A) x=-1 为可去间断点, x=1 为无穷间断点-|

(2)函数 (x)=dfrac ({x)^2-x}({x)^2-1}sqrt (1+dfrac {1)({x)^2}} 的无穷间断点的个数为 ()-|||-(A

(2)函数 (x)=dfrac ({x)^2-x}({x)^2-1}sqrt (1+dfrac {1)({x)^2}} 的无穷间断点的个数为 ()-|||-(A

4.设 (x)=dfrac (arctan (1-x))({x)^2-1}, 则 x=1 是f(x)的 ()-|||-A.连续点 B.可去间断点 C.跳跃间断点

函数__-|||-(x)=dfrac ({x)^2-x}({x)^2-1} sqrt (1+dfrac {1)({x)^2}}-|||-__的无穷间断点的个数为

15.设函数(x)=dfrac (sin ({x)^2-3x+2)}((x-1)|x-2|)-|||-__，则f(x)有（ ）A、2个跳跃间断点B、2个无穷间断

(1)设函数 (x)=dfrac (ln |x|)(|x-1|)sin x, 则 f(x)有 ()-|||-(A)1个可去间断点,1 个跳跃间断点 (B)1个可

设 f(x)= } a + 2xsin(1)/(x), & x 0 x = 0 是 f(x) 的可去间断点，则 a = ( )A. 0B. -1C. 1D.

1.设 (dfrac (1)(x))=x((dfrac {x)(x+1))}^2, 则 f(x)= ()-|||-(A) dfrac (1)(x)((dfrac

4.设函数(x)=dfrac (ln |x|)(|x-1|)sin x,则f(x)有()A.1个可去间断点,1个跳跃间断点B.1个可去间断点,1个无穷间断点C.