Error messages

17.1What each error means#

When an error appears, press AC to cancel and clear the line, or ◀ or ▶ to go back to the expression so you can correct it.

Message	What it means	How to fix
Math ERROR	The calculation has no real answer or is too big: divide by zero, ln 0, tan 90°, a square root of a negative number in Calculate, 200!, a result above 9.999999999×10^99, a singular matrix, or a value outside the allowed range in an app.	Check the numbers. For roots of negative numbers use the Complex app.
Syntax ERROR	The expression is not complete or an operator is in the wrong place, such as two plus signs in a row, an empty fraction box, or a digit that is not allowed in the base.	Press left to go to the mistake and correct it.
Argument ERROR	A function got the wrong number of values, such as sin(1,2).	Give the function exactly the values it needs.
Dimension ERROR	Matrix or vector sizes do not match the operation.	Check rows and columns. You can only add matrices of the same size and multiply when the columns of the first equal the rows of the second.
Variable ERROR	A matrix or vector you used has not been defined.	Define it first with OPTN 1.
Memory ERROR	The result needs too much room, for example a table with more than 45 rows.	Shorten the range or use a larger step.
Can't Solve	SOLVE could not find a solution near your guess.	Try another guess, or check that the equation has a solution.
Time Out	A numeric integral or derivative could not be calculated accurately enough.	Narrow the limits or simplify the function.
No Solution	The simultaneous equations contradict each other.	Check the coefficients you typed.
Infinite Solution	The simultaneous equations have more than one answer.	Check the coefficients; the equations are the same line or plane.

Example 17.1

Divide by zero

1. 1 ÷ 0.

   1÷0=

Example 17.2

Syntax error

1. Two plus signs in a row.

   1++=

Example 17.3

Argument error

1. sin with two values.

   sin1SHIFT,)2)=

Example 17.4

Dimension error

1. Add a 2×2 to a 3×3.

   MENU4OPTN11221=2=3=4=OPTN12331=1=1=1=1=1=1=1=1=OPTN3+OPTN4=

Example 17.5

Variable error

1. Use a matrix that was never defined.

   MENU4OPTN5=

Example 17.6

Cannot solve

1. Solve x² + 1 = 0, which has no real solution.

   ALPHAx)x²+1ALPHA=CALC0SHIFTSOLVECALC0=

Example 17.7

Go back to the expression

1. Press the left arrow after an error.

   1÷0=◀

fx-991EX ClassWiz is a trademark of Casio Computer Co., Ltd.. Trident Calculator is an independent product by South View Studios and is not affiliated with, sponsored by or endorsed by Casio. The name is used only to describe the kind of calculator this model resembles; Trident's names, keys, display, fonts and software are its own clean-room design.