1

When I try to compile the code below, I get an error message saying "missing number" and "illegal of measure" in reference to the specific part [\hskip.017in -1,\sin{a}\hskip.017in]. I cannot for the life of me figure out what I'm doing wrong. Please help. Thank you!

$$ f^{-1}\big((-\infty,a\hskip.017in]\big)\ =\ \left\{\begin{array}{ccc}
[\hskip.017in -1,1\hskip.017in] & {} & a>\frac{\pi}{2} \\
{} & {} & {} \\
[\hskip.017in -1,\sin{a}\hskip.017in] & {} & a\in\left[\hskip.017in -\frac{\pi}{2},\frac{\pi}{2}\hskip.017in \right] \\
{} & {} & {} \\
\varnothing & {} & a<-\frac{\pi}{2} \\
\end{array}\right.\ \in\ \mathcal{L} $$
David Carlisle
  • 757,742
user272533
  • 13

1 Answers1

2

Just add {} right before [\hskip.017in -1,\sin{a}\hskip.017in]. Otherwise, LaTeX will think that you are trying to increase the space between lines using an expression which is not a length.

Besides, I have a suggestion for you: use \[...\] instead of $$...$$.

José Carlos Santos
  • 4,803