2xx2−12 x \sqrt{x^{2}-1}2xx2−1
2x1−x22 x \sqrt{1-x^{2}}2x1−x2
2x1−x2\frac{2 x}{1-x^{2}}1−x22x
2x1+x2\frac{2 x}{1+x^{2}}1+x22x