How do you know you can't take the derivative of an equation?

Question

anonymous · Answer

you can always take the derivative of a function. taking derivative == finding slope of a function. so unless the function has an undefined slope, you can always find the derivative.

anonymous · Answer

Thanks :)

anonymous · Answer

if the function is not continous

anonymous · Answer

at that point

anonymous · Answer

that too. DeritaveOfJuan is right.

anonymous · Answer

If derivative exists the function is continuous on that domain..but does the vice-versa is true?

anonymous · Answer

no, even if the function is cont, it does not mean it has a derivative, Think about the graph of y=IxI

anonymous · Answer

its cont but differentiable at x=0

anonymous · Answer

not*

chriss · Answer

Which is because a vertex is formed at x=0.  Vertexes and noncontinuous are defined as undifferentiable.