The function is
and point
.
(a) Draw the secant lines with
and
.
The point
takes
- values of
and
.
Take
the point is
.
Take
the point is
.
Take
the point is
.
Draw the secant lines with the following points 
and
.
.gif\")
(b)
\Find the slope of secant line passing through
and
.
Slope
.
Find the slope of secant line passing through
and
.
Slope 
.
Find the slope of the secant line passing through
and
.
Slope
.
(c) With the above observation the slope of the tangent line is greater than
\
and less than
, we can clearly observe it in the graph.
On an average, the slope can be
approximately.
As the point
approaches to the point
, the slope of the secant line approaches
to the slope of tangents.
\Therefore to improve approximation of slope, the point
should approach to Point
.
(a) The Graph of the Function and secant lines are drawn.
\Graph:
\
.
(b)
\The slope of secant line passing through
and
is
.
The slope of secant line passing through
and
is
.
The slope of secant line passing through
and
is
.
(c) Slope of the tangent line is
approximately.