Answer
odd
Work Step by Step
We know that if a function is odd, then $f(-x)=-f(x).$
We know that if a function is even, then $f(-x)=f(x).$
Hence we plug in $-x$ to see what happens.
$f(-x)=\frac{-x}{1+(-x)^2}=\frac{-x}{1+x^2}=-f(x).$ Therefore the function is odd.
