判别函数f(x)=
{1-xx≤0
{1+xx＞0
，的奇偶性．
f(x)= {1-x x≤0 {1+x x＞0 f(-x)= {1-(-x) -x≤0 {1+(-x -x＞0 即f(-x)= {1-x x≤0 {1+x x＞0 所以 f(-z)=f(x)． f(x)为偶函数．
判别函数f(x)=
{1-xx≤0
{1+xx＞0
，的奇偶性．
f(x)= {1-x x≤0 {1+x x＞0 f(-x)= {1-(-x) -x≤0 {1+(-x -x＞0 即f(-x)= {1-x x≤0 {1+x x＞0 所以 f(-z)=f(x)． f(x)为偶函数．
