Home TI-Nspire Authoring ← Advanced Techniques 2

## Creating Interactive Documents using TI-Nspire

Steve Arnold

2. Building a Step-by-Step Template

Our next advanced technique again makes use of G&G and a slider, although it could well be set up within a spreadsheet if the amount of text was limited.

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What we want is for our series of statements to appear as we move the step values from 1 to 4. Here we will be using dynamic text, as outlined in an earlier document, with a little more emphasis upon creating a suitable layout for our text.

Begin by inserting a slider, called step, to run from 1 to 4 in steps of 1; minimize the slider as shown. It is useful to show the grid points from the view menu, to help in our layout design. Use Point On to place a point on a grid point where we want the first part of our top line of text to appear (I called this Col 1 Line 1). From this point, construct horizontal and vertical perpendicular lines. Place another Point On the horizontal line where the second column of text should start (Col 2 Line 1) and another perpendicular from that point, as shown. Finally, place another Point On the left vertical line (here labelled Col 1 Line 2).

We now use the Symmetry transformation to keep complete control over the spacing of subsequent rows of text. Choose menu>Transformations>Symmetry. Click on the point Col 1 Line 2 and then on the point above it, Col 1 Line 1. A new point will appear the same distance below. For four lines of text, repeat this process: click on the new point just created (call it Col 1 Line 3) and then on Col 1 Line 2 point to create the point Col 1 Line 4.

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Try grabbing the point at Col 1 Line 2 and dragging it up and down - see how it controls the line spacing? The original point (Col 1 Line 1) controls the vertical position, and Col 2 Line 1 controls the placement of the second column of text.

We are now ready to build our dynamic text - we will need 3 "when" statements, assuming that the first line of our instructions remains permanently visible: just replace the text for Col 1 Line 1 and Col 2 Line 1 with whatever your first two items are to be.

We want our next line of text to appear when we change the step value to 2, and then to remain visible from that point on, so we use when(step>1,1). Calculate using this, press L and when step becomes 2 or greater, the output value changes from "undef" to "1".

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The text for line 2 will be a label for circles, as described previously, centered at the point we have created and with radius equal to the output of our when statement. Choose menu>Shapes>Circle, click on the value of 1 from the when statement and click on the point at Col 1 Line 2. Label the circle with the required text. Now place a Point On the circle and a line through that point perpendicular to the horizontal, as shown. Place another circle at the intersection of the this line with our column 2 line, again using the output 1 as the radius. Label with the text required. Use your step slider to test that both circles disappear when step goes back to 1. If so, then change the when statement to output a very small value like 0.0001 instead of 1, hide the visible points and the horizontal line and repeat for lines 3 and 4.

You may wish to keep the control points unhidden but very small, covered by the text, so that it is easy to rearrange the placement of the columns and rows as desired. This page is easily customized - if only 3 lines are required, change the slider to stop at 3 and hide the bottom line of text. More lines may be added if required, making this a very versatile and useful applet.

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