Step 1:
First, we distribute the terms in the numerator:
$$\frac{\left(x^{2}+1\right)^{2}(-2)+(2 x) 2\left(x^{2}+1\right)(2 x)}{\left(x^{2}+1\right)^{4}} = \frac{-2\left(x^{2}+1\right)^{2}+8x^{2}\left(x^{2}+1\right)}{\left(x^{2}+1\right)^{4}}$$
Show more…