题目9、lim_(xto1)((1)/(x-1)-(2)/(x^2)-1)=( ).A. -1;B. 0;C. (1)/(2);D. ∞.9、$\lim_{x\to1}(\frac{1}{x-1}-\frac{2}{x^{2}-1})=( )$.A. -1;B. 0;C. $\frac{1}{2}$;D. ∞.题目解答答案C. $\frac{1}{2}$;