Let $f:R\rightarrow R $ and $g:R\rightarrow R$ be the functions defined by $f(x)= \frac{x}{1+x^{2}}$,
$x \in R, g(x)=\frac{x^{2}}{1+x^{2}},x\in R$ Then, the correct statement (s) among the following is/are
(a) both f.g are one-one
(b) both f.g are onto
(c) both f.g are not one-one as well as onto
(d) f and g are onto but not one-one