求lim(x趋近于0)f(x)时,一定要先求x趋向于0负和0正?

求lim(x趋近于0)f(x)时,一定要先求x趋向于0负和0正? 求lim x^sinx x正趋近于0 x趋向于0 lim f(x)/x=0,求x趋向0时 lim ｛[√1+f(x)]-1｝/x 设f'(x0) 存在,求lim[ f(x0-x)-f(x0)]/x,x趋向于0 lim sinx^x(x趋近于0+)求极限 lim sinx^x(x趋近于0+) 求极限 求极限 lim x趋近于0 (ex-1)/x 求极限 lim x趋近于0 sin3x／7x 求LIM(1-COSX)/X*SINX X趋近于0 求lim(x趋近于0)sin根号x 设f(x)在x=a处可导,f(a)>0,求N趋近于正无穷时lim{f(a+1/n)/f(a)}的N次方. 求lim x趋向于0(arctanx)/(x^2+1)