Texas Instruments TINSPIRE Teacher Software Guidebook - Page 437

Using Variables A variable is a defined value that can be used multiple times in a problem. You can define a value or function as a variable within each application. Within a problem, variables are shared by TI-Nspire™ applications. For example, you can create a variable in Calculator, then use or modify it in Graphs & Geometry or Lists & Spreadsheet within the same problem. Each variable has a name and a definition and the definition can be changed. When you change the definition, all occurrences of the variable in the problem are updated to use the new definition. In the TI-Nspire™ software, a variable has four attributes: • Name - User-defined name assigned when the variable is created. • Location - Variables are stored in memory. • Value - Number, text, mathematical expression, or function. • Type - Type of data that can be stored as a variable. Note: Variables created with the Local command within a user-defined function or program are not accessible outside that function or program. Linking values on pages Values and functions created or defined in one application can interact with other applications (within the same problem) to share data. When using linked items, keep in mind: • Values can be linked between applications on one page or between different pages of the same problem. • All applications are linked to the same data. • If the linked value is changed in the original application, the change is reflected in all linked usages. Defining a variable is the first step in linking values. Creating variables Any portion or attribute of an object or function created within an application can be stored as a varible. Examples of attributes that can become variables are the area of a rectangle, the radius of a circle, the value contained in a spreadsheet cell or the contents of a row or column, or a function expression. When you create a variable, it is stored in memory. Using Variables 425