6

Entering and Evaluating Equations

How You Can Use Equations

You can use equations on the HP 33s in several ways:

„For specifying an equation to evaluate (this chapter).

„For specifying an equation to solve for unknown values (chapter 7).

„For specifying a function to integrate (chapter 8).

Example: Calculating with an Equation.

Suppose you frequently need to determine the volume of a straight section of pipe. The equation is

V = .25 π d2 l

where d is the inside diameter of the pipe, and l is its length.

You could key in the calculation over and over; for example, .25 ‘ Nz2.5 !z16 zcalculates the volume of 16 inches of 2 1/2–inch diameter pipe (78.5398 cubic inches). However, by storing the equation, you get the HP 33s to "remember" the relationship between diameter, length, and volume — so you can use it many times.

Put the calculator in Equation mode and type in the equation using the following keystrokes:

Keys:

Display:

Description:

H

 !!

Selects Equation mode, shown

 

or the current equation

by the EQN annunciator.

Entering and Evaluating Equations6–1