Plotting a Derivative
If the animation does not appear, click
here.
This animation shows how to use the slope of a curve to plot the derivative for that curve.
(See notes below.)
In this animation, the purple line segment is always tangent to the upper curve, the point of
tangency being at the center of the segment. The black horizontal segment that forms the base
of the moving triangle always has length one, so the altitude of the triangle, shown as a blue
segment, is always numerically equal to the slope of the tangent line. This altitude is
transferred to a separate coordinate system below; as the point of tangency moves to the right, the lower
blue segment moves in step with it; the end of this segment that doesn't lie on the x-axis
traces out a curve which
is the derivative of
the upper curve. (11/17/07)