## Wednesday, September 7, 2022

### Casio fx-991EX Classwiz Tips: Solve for Any Variable

Casio fx-991EX Classwiz Tips:  Solve for Any Variable

This week I am going to show some things that can be done with the Casio fx-991EX Classwiz.

Solving For Any Variable

The Casio Classwiz can solve equations in the main (Calculate) mode in the following formats:

Equation, i.e.  A + 2x = y^3

And Expression Equal to Zero, i.e. 2x^4 - 18  (the equal to zero is implied)

Pressing [SHIFT] [CALC] (SOLVE) allows us to enter values for all but one variable to solve for.   Enter values with the equals [ = ] key.

When you select the variable to solve for, press the [ = ] key without entering a number.

Caution:  When you are entering equations, don't use the white [ = ] key.  To enter the = character, press [ALPHA] [ CALC ].

The L-R indicator tells the the accuracy of the solution.  We want L-R = 0.

Example:

2x^2 + 3y^3 = A

Keystrokes:  2 [ x ] [ x^2 ] [ + ] 3 [ALPHA] (Y) [SHIFT] (x^3) [ALPHA] (=) [ALPHA] (A)

[SHIFT] (SOLVE)

Inputs:  x = 8, y = 2, solve for A.   A = 152, L-R = 0

Inputs:  x = 6, A = 79, solve for y.  y = 1.326352406, L-R = 0

Inputs: y = 3.5, A = 105, solve for x.  Cannot Solve   (x has a complex number solution)

Eddie

All original content copyright, © 2011-2022.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

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