1.f(x)=(x^2-1)/(x^2-3x+2),
(x^2-1)=(x+1)(x-1)
(x^2-3x+2)=(x-1)(x-2),é´æç¹æ¯x=1,x=2.
lim(xâ1)=(x^2-1)/(x^2-3x+2)=lim(xâ1)=(x+1)/(x-2)=-2;
lim(xâ2)=(x^2-1)/(x^2-3x+2)=lim(xâ1)=(x+1)/(x-2)=æ ç©·;
æ以x=1æ¯
第ä¸ç±»é´æç¹,x=2æ¯
第äºç±»é´æç¹ã.
2ï¼f(x)=(â(1+x)-â(1-x^2))/2xï¼x=0æ¯é´æç¹ï¼
lim(xâ0))(f(x)=lim(xâ0)(â(1+x)-â(1-x^2))/2x=lim(xâ0)(x+x^2)/2x[â(1+x)+â(1-x^2)]
=lim(xâ0)(1+x)/2[â(1+x)+â(1-x^2)]=1/4,
æ以x=0æ¯ç¬¬ä¸ç±»é´æç¹.