HP Prime Graphing NW280AAABA manual Variables

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Variables

Variables are objects that have names and contain data. They are used to store data, either for later use or to control settings in the Prime system. There are four types of variables, all of which can be found in the Vars menu by pressing a:

•Home variables

•CAS variables

•App variables

•User variables

The Home and app variables all have names reserved for them. They

are also typed; that is, they can contain only certain types of objects. For example, the Home variable A can only contain a real number. You use Home variables to store data that is important to you, such as matrices, lists, real numbers, etc. You use app variables to store data in apps or to change app settings. You can accomplish these same tasks via the user interface of an app, but app variables give you a quick way of doing these tasks, either from Home or within a program. For example, you can store the expression “SIN(X)” in the Function app variable F1 in Home View, or you could open the Function app, navigate to F1(X), and enter SIN(X) in that field.

CAS and user variables can be created by the user and they have no particular type. Their names may be of any length as well. Thus, diff(t2,t) returns 2*t and diff((bt)2, bt) returns 2*bt for the CAS variables t and bt. Further evaluation of 2*bt will only return 2*bt, unless an object has been stored in bt. For example, if you enter bt:={1,2,3} and then enter diff((bt)2, bt), the CAS will still return 2*bt. But if

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