Step 1:
\
-coordinate is
.


-coordinate is
.

.
The distance from the point
is
.


.

Step 2:
\The rate of change in distance with respect to
is
.
.
Apply derivative on each side with respect to
.




The rate of change at
.
Find
and
.
.
.
.
.
Step 3:
\



.
The rate of change in distance at
is 
Substitute
and
in above expression.



.
The rate of change in distance at
is
.
Solution:
\The rate of change in distance at
is
.