Question

lim

x→0

1- 1+x

x

=______．

Answer 1

lim

x→0

1- 1+x

x

=

lim

x→0

(1- 1+x )(1+ 1+x )

x(1+ 1+x )

=

lim

x→0

-1

1+ 1+x

=-

1

2

故答案为：-

1

2