These are 2-D math parser errors caused by an incorrectly formed equation or inequality.

Example 1

In this example, an incomplete equation has been entered.

Solution:

To fix the error, enter a complete equation.

Example 2

In this example, an incomplete inequality has been entered as the first argument.

Solution:

Enter a complete inequality.

The solution is the open interval from -2 to 2.  For more examples of solving inequalities, see solve/ineq.

equation, solve/ineq