例18.求下列极限 (1)im(1+-)5x+2 x→0 解Jim(1+-)3*2=[im(1+-)下=e x→0 x→0 (2)im(1-2x)x x→0 fF lim(1-2x)=lim(1-2x)-2x=e- x→0 (3)lim(1+ x→x+2 解lim(l+ im(1+ (x+2)-2 x→0 x+2 x→0 x+212 例18.求下列极限 1 5 2 (1).lim(1 ) ; x x x + → + 1 0 (2).lim(1 2 ) ; x x x → − 1 (3).lim(1 ) ; 2 x x→ x + + 1 1 5 2 5 5 .lim(1 ) [lim(1 ) ] x x x x e x x + → → 解 + = + = 1 1 2 2 2 0 0 lim(1 2 ) [lim(1 2 ) ] x x x x x x e − − − → → 解 − = − = 1 1 ( 2) 2 lim(1 ) lim(1 ) 2 2 x x x x e x x + − → → + = + = + + 解