f(a)=-f(-a)？ (This is a strange function)

Because f(a)>f(-a)? So -f(-a)>f(-a)

f(-a)& lt； 0 Press the image -a to belong to (-infinity,-1)U(0, 1).

So a belongs to (-1, 0)U( 1, positive infinity).

If you don't understand, you can ask.