Chord lets you click
at two places on the curve. It then draws a chord through these points and evaluates and
displays the slope of the line.This SIR allows you to present graphs of equations y = f(x) of five types: the straight line ax + b, the quadratic ax2 + bx + c, the inverse function a/x + b, the exponential aebx, and the natural logarithm a´ln(bx) + c. You may set the parameters in an equations simply by clicking on each, whereupon a keypad appears. The enter key of the keypad sets the value of the parameter to the displayed value. Choose parameters with care, so as not to put the graph off scale.
You may oslo set the width and offsets of the x- and y-scales. You may evaluate points on the graphs, find the slope of the chord or the tangent at any point, and have the computer evaluate the definite integral between any two points on the graph.
On each graph you have four options:
Crosshairs gives you a vertical and horizontal line which cross on the curve at the horizontal position you click.
Chord lets you click
at two places on the curve. It then draws a chord through these points and evaluates and
displays the slope of the line.
Tangent draws the tangent at the point you select, and displays its slope. The chord and tangent can be used to show how to define and evaluate the slope of a curve at a point.
Integrate lets you select two points on the curve and evaluate the integral between them. The integral is slowly built up graphically in colour from the first point to the second; its approximate value is shown as it accumulates; and there are periodic pauses to let you read the accumulating values.
There is also a
display which places, side by side and to the same scale, graphs of ex and
ln(x). You may click on either graph to position crosshairs on its curve. The crosshairs
on both graphs will move to the corresponding points and the (x,y) values on both are
displayed, to illustrate that ex and ln(x) are reciprocal functions.
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Updated July 25, 2000