## Test Menu

The relationship between any two numbers can be
compared by selecting one of the test options. Press
to view the test menu.

Press the menu key associated with a symbol.

Two numbers are taken off the stack
and compared. A **1** will be returned
if the test is true and a **0** if it is false. For example, the
test, `4 7 > `, returns a value of **0** since 4 is not
greater than 7.

Tests can also be made within algebraic statements such as

' x = 9 ' or `'x < 2.5'`

The result of such tests depends upon the value of the variable x.
This type of comparison is often used to control the domain
over which a graph is drawn. See note.

**Note:** To graph a function over a domain, first press
to edit the function.

Put parentheses around the entire function and multiply it by each restriction
raised to the power of -1, or divide by each restriction.

Press .

When the statements are true it simply multiplies the function by 1^{-1} or 1,
but when either of the restrictions is false the calculator will try to calculate 0^{-1},
which is undefined, and cannot graph a value for that part of the function. Press
.