HP 33s - Manual (Page 103)

Entering and Evaluating Equations 6–11
The evaluation of an equation takes no values from the stack — it uses only
numbers in the equation and variable values. The value of the equation is returned
to the X–register. The LAST X register isn't affected.
Using ENTER for Evaluation
If an equation is displayed in the equation list, you can press ‘ to evaluate
the equation. (If you're in the process of typing the equation, pressing ‘ only
ends the equation — it doesn't evaluate it.)
„ If the equation is an assignment, only the right–hand side is evaluated. The
result is returned to the X–register and stored in the left–hand variable, then
the variable is VIEWed in the display. Essentially,
‘ finds the value of
the left–hand variable.
„ If the equation is an equality or expression, the entire equation is
evaluated — just as it is for
X . The result is returned to the X–register.
Example: Evaluating an Equation with ENTER.
Use the equation from the beginning of this chapter to find the volume of a 35–mm
diameter pipe that's 20 meters long.
Keys: Display: Description:
| H
( ™ as required)
#/
)º
πº:º Displays the desired
equation.
‘
@
)
 Starts evaluating the
assignment equation so the
value will be stored in V.
Prompts for variables on the
right–hand side of the
equation. The current value
for D is 2.5000.
35 g
@
 )
 Stores D, prompts for L,
whose current value is
16.0000.
20 ‘ 1000
z g

#/
 88)
 Stores L in millimeters;
calculates V in cubic
millimeters, stores the result
in V, and displays V.