Answer:
Does not exist.
Explanation:
d/dx |u| = (u / |u|) * du/dx
Here u = x^2 - 1 and du/dx = 2x , so we have
2x (x^2 - 1) / |x^2 - 1| as the required derivative.
At the point (1,0)
the denominator = |1^2 - 1| = 0
- so the derivative does not exist at (1, 0)