Display mode

All of the expressions we have written so far have been on the same line as the text that came before and after them, otherwise known as inline expressions. This is fine for short, simple expressions, but if you want to write larger ones, or if you want your expressions to stand out from the text, you need to write them in display mode. In addition, only displayed expressions can be labeled and numbered (see the User's Guide), and multi-line equations (see Sec. ) must be in display mode.

Click on the Display button in the Math Panel, which represents a couple lines of text before and after a centered blue box. LYX inserts a formula, but the insertion point is on a new line, and it's centered within that line. Now type an expression and run L^ATEX to see how it looks. The Display button is actually a toggle; use it now to change a couple of your expressions to display mode and back.

Display mode has a couple differences from inline mode:

• The default font is larger for a few symbols, like $\sum$ and $\int$
• Subscripts and superscripts for limits and sums (but not integrals) are written under rather than next to the symbols
• Text is centered

Other than these differences, though, displayed expressions and inline expressions are very similar.

One final note about the way displayed formulae are typeset: be careful about whether you're putting your equation into a new paragraph or not. If your formula is in the middle of a sentence or paragraph, then don't press Return. Doing so will cause the text after the formula to start a new paragraph. That text will therefore be indented, which is probably not what you want.

Exercise: Put the various equations in example_raw.lyx into display mode, and see how they're typeset differently.

Exercise: Using various tools you've learned in this section, you should be able to write an equation like^4.2:

f (x) = $$\left\{\vphantom{ \begin{array}{cc} \log_{8}x & x>0\\ 0 & x=0\\ \sum_{i=1}^{5}\alpha_{i}+\sqrt{-\frac{1}{x}} & x<0\end{array}}\right.$$$$\begin{array}{cc} \log_{8}x & x>0\\ 0 & x=0\\ \sum_{i=1}^{5}\alpha_{i}+\sqrt{-\frac{1}{x}} & x<0\end{array}$$