The function is
and the point is
.

Apply derivative on each side with respect to
.

Apply quotient rule of differentiation:
.
In this case
and
.



.
Substitute
in
.


.
The derivative of the function at
is
.
Graph :
\Graph the function
.
Observe the graph:
\The derivative function of
at
is
.
.
The derivative of the function at
is
.