Usually, our goal when writing rationale is to write down the work we expect the student to do when solving the problem, perhaps with some brief explanation. 

Step 1: Create the rationale.

The rationale for our question might be:

       Rationale:  The answer is True.

The point (-7,36) satisfies the function y=-5x+1 because if we substitute –7 for x and 36 for y into y=-5x+1, we get: 36=(-5)(-7)+1, that is 36=35+1 or 36=36, which is a true equation.       

or

       Rationale: Substituting –7 for x and 36 for y, we have:

The answer is True.

The second rationale requires more familiarity with using Equation Editor so we have included a small tutorial on this at the end of this chapter (Part I).

Of course, our rationale must use the dynamic variables of the question.  Probably, we will need one or more new display variables.  It is usually difficult to know exactly what variables we need until we start typing. So we will just start writing our rationale and as we write it, we will notice when and what display variable we need.

Step 2: Write the rationale.

• Double-click on question 1 to open it for editing.
• Click in the Rationale field to move the cursor there.
• Type in the first rationale (see next page).

The first rationale offers an excellent opportunity to practice our [Ctrl]+[C] and [Ctrl]+[V] (Copy & Paste) skills.  Copy all or parts of the question into the rationale to avoid having to insert all those variables again.  You can even copy equations!

• Open EE ([Ctrl]+[E] or click on the Insert menu, then Equation).
• Type in the equation as below (left), inserting the variables. 

• Click on Record (in EE).
• Continue typing the rationale.

Here we have come to a display problem.  We have no variable to display the value of a⋅xx. Notice that this variable does not need special formatting, i.e. it is “general” (see Table 1 above).   Also, because it is a display variable, no uniqueness condition is necessary.

• Press [Ctrl]+[D] to open the Edit Algorithm Definitions box.
• Click on New.
• Define the variable axx= a*xx. Click on Done.

♦ Although axx is a used only for display, it is still a numeric value, so we do not put the “code” Disp in front of it, which is our way of making sure that we don’t use a string value (that is, a bunch of characters) for calculations.

• Press [Ctrl]+[E] to open EE.
• Type in the equation, inserting the three variables.

 

• Click on Record (in EE).

♦ Not strictly necessary: we typed “satisfies” and “true” using bold and italic and italicized the variables x and y (see Hints and Tips below to see how to do this).  We also input the last equation yy=yy using EE to make the spacing nice.

• Click on Record.

Here is our question complete with rationale (and with newly calculated values).

In addition to written rationale, if we have a whiteboard presentation or other notes on this material available over the Internet or Intranet, we can insert a hyperlink.  Or, we can copy or write some notes into a Narrative. We will talk about this in more detail in later chapters.

Step 3: Save the file

• Save the file by pressing [Ctrl]+[S] or click on the File menu, then on Save.