Editing Limit of a function (section)

====Non-equality of one-sided limits====
The function 
<math display=block>f(x)=\begin{cases}
1 & \text{ for } x < 0 \\
2 &  \text{ for } x \ge 0
\end{cases}</math>
has a limit at every non-zero {{mvar|x}}-coordinate (the limit equals 1 for negative {{mvar|x}} and equals 2 for positive {{mvar|x}}). The limit at {{math|1=''x'' = 0}} does not exist (the left-hand limit equals 1, whereas the right-hand limit equals 2).