You can express piecewise-continuous functions using the $\mathrm{piecewise}$function. The $\mathrm{piecewise}$function takes as its parameters a condition (or conditions) and an associated expression (or expressions), should the condition evaluate to true.  For more information on the $\mathrm{piecewise}$function, see the piecewise help page.

The conditions must be an equality or inequality, or a Boolean combination of inequalities.  The wrong kind of parameters in piecewise error occurs when any of the conditional arguments are not Boolean-valued (they do not evaluate to true or false).

You can also encounter this error when using the 2-D math notation for a piecewise expression.  Again, it indicates that the conditions are not Boolean-valued.  See the second example.

Example 1:

In this case, the unassigned $x$ is not an equality, inequality, or some Boolean combination of inequalities.

Solution:

Replace the first argument with a valid condition.  One possible solution is to express the function as

Example 2:

In the following example, the second condition isn't properly formed.

Solution:

$x\=2$.