Full Evaluation

Will full evaluation, variables previously defined are evaluated before the definition is stored. Thus, definitions of expressions can depend on the order in which they are made. Use an equals sign preceded by a colon to make an assignment for full evaluation.

$\blacktriangleright$ To assign the value 25 to z

1.
Type z : = 25a in mathematics.

2.
Leave the insertion point in the equation.

3.
Click the New Definition button itbpF0.3009in0.3009in0.0701innewdef.wmf on the Compute toolbar or, from the Define submenu, choose New Definition.

Thereafter, until you exit the documentor undefine the variable, if a has not been previously defined, the system recognizes z as 25a. If a has previously been defined to be x + y, then the system recognizes z as 25$\left(\vphantom{ x+y}\right.$x + y$\left.\vphantom{ x+y}\right)$. Try the following examples that contrast the two types of assignments, and look at the list displayed under Define + Show Definitions for each case.



\begin{example}
Make the assignments $a=1$, $x:=a$, $y=a$, and $a=2$\ (in that ...
...begin{eqnarray*}
x &=&\allowbreak 1 \\
y &=&2
\end{eqnarray*}
\end{example}


\begin{example}
Make the assignments $a=b$, $x:=a^{2}$, $y=a^{2}$, and $a=6$\ (...
...kip
\begin{eqnarray*}
x &=&b^{2} \\
y &=&36
\end{eqnarray*}
\end{example}