1. ## true/false

If f(x) is defined for all x, then f'(x) is defined for all x
why/why not?

2. Originally Posted by puravida12
If f(x) is defined for all x, then f'(x) is defined for all x
why/why not?

Check $f(x):=|x|$ at x = 0.[\math]

Tonio