The function is and
.
Alternative form of derivative at :
.
.
Graph :
\Graph the function :
Observe the graph:
\As approaches to
from left hand side,
tends to
.
As approaches to
from right hand side,
tends to
.
Since does not approaches to a particular value,
is not differentiable at
.
The derivative of the function at does not exist.
The derivative of the function at does not exist.