Data tool

1. Data tool basics

The Date tool enables you to investigate data, data plots, and mathematical relationships. If you want to investigate any plot you see in the Main view, just double-click that plot to enter the Data tool.

To return to the Main view, just click the Data tool’s Close button in the upper right.

2. Slope

You can use the Data tool to inspect the slope of a graph at any point between the two endpoints. Just click the Slope button in the Data tool (as shown above) and trace along the path of the curve. A black tangent line segment appears on the plot at your cursor location. The plot’s slope at that point appears in a yellow box at the bottom of the graph.

3. Download graph as an image

The button “Download graph as an image” does just what it says. The graph portion of the Data tool is captured and downloaded to your computer or mobile device.

Be sure you know where downloaded images are stored on your device. You also may wish to rename these files each time you download one. The default image names are understandable, but not very descriptive (especially if you are capturing several images based on the same graph.)

4. Fit - Autofit

To try to fit a mathematical relationship to a graph, click the Fit button at the top of the Data tool.

Three common function types are available for “Autofitting.”

You just select the Fit you want and click the “Autofit” button to see how well that relationship matches your data. In the case below, Line and Exponential are horrible fits, as you might expect. The parabola fit (blue) does the best it can, but it’s still not very close.

4. Fit - Fit Builder

If none of the three common Autofit functions provides a good fit, you have a mathematical puzzle to solve.

You may see that the shape of the swing’s x vs. t graph above (red) looks like a sine curve. That can be expressed mathematically like this in an (x,y) coordinate system:

y = a*sin(b*x + c)

You can build this relationship in Fit Builder for the (t, x) plot shown above. Here’s the process (and illustrated in the image below):

The final parameter expression values in the image below have been hidden (yellow boxes) to leave you with that mathematical modeling challenge. (Swing plot is red; mathematical fit is blue.)