The function is
.
Differentiate on each side with respect to
.

Power rule of derivatives :
.

The differential function is 
The differential function is
.
Substitute
and
in differential function.

Hence, the value of
is
.
If
changes by a small amount
, then will cause
to change by a small amount
.
Find
using the formula
.
Substitute
and
in the above formula.

The function is
.
Find the value of
and
.

Substitute
and
in
.
.
Find point on the curve at
.
.
Therefore, the point is
.
Graph:
\Graph the curve.
\Draw the tangent line at
.
.gif\")
The value of
is
.
The value of
is
.