Creating Menus For Multiple Equations - HP 17bII Owner's Manual

"Chi-Squared Statistics" in chapter 14 illustrates another use of the Σ
function with SUM lists.
Creating Menus for Multiple Equations (S Function)
The S ( solving for ) function is used in conjunction with the IF function
to group related equations together and to specify the criteria for
choosing one of them to solve.
S( variable name )
The advantage over two separate equations is that the single equation
gives you a single menu with all possible variables. That way, if you are
working with two different but related problems, you can keep the same
Solver menu labels in the display all the time─you don't have to switch
equations.
For example, consider these two equations for conversions:
 and 
The following, rearranged single equation can do either conversion:
  
This means: if you are solving for either KG or LB , then use
KG × 2.21－ LB ＝0. Otherwise (that is, if you are solving for M or FT ),
use M × 3.28－ FT = 0. The two conversion equations are rewritten so
that all the variables appear on one side of each equation, and the
other side is set equal to zero.
The S function appears as part of the conditional expression of the IF
function. You can leave out the "＝0" and it will be understood that the
whole equation is set equal to zero.
Example: Unit Conversions. Use the above equation to convert
between kilograms and pounds and between meters and feet.
Press   then enter the equation:
178 12: The Equation Solver
File name : English-M02-1-040308(Print).doc Print data : 2004/3/9