The function is
.
Find
at
and
.

Apply derivative on each side with respect to
.

Power rule of derivatives :
.

The differential function is
.
Substitute
in differential function.

.
Hence, the value of
is
.
Find
at
and
.
If
changes by a small amount
this will cause
to change by a small amount
.


Substitute
and
in
function.

.
Hence, the value of
is
.
The value of
is
.
The value of
is
.