f(-x)=-f(x)

So 2f (x)/x

x & lt0

Then f (x) >; 0

X>0 is an increasing function, then X.

f(- 1)=-f( 1)=0

So f (x) gt; f(- 1)

So- 1

x & gt0

Then f (x) < 0.

X>0 is an increasing function.

So f (x) < f( 1)

So 0

So- 1