计算：x+2y1-x2+y-1x2-1-y1-x2．

题型：解答题难度：一般来源：不详

计算：

x+2y

1-x2

+

y-1

x2-1

-

y

1-x2

．

答案

原式=

x+2y

1-x2

-

y-1

1-x2

-

y

1-x2

=

x+2y-y+1-y

1-x2

=

x+1

1-x2

=

1

1-x

．