LaTeX math symbols for everyday equations

Greek letters: capitalization changes the command

Lowercase letters such as \alpha, \beta, \theta, \lambda and \pi are common for angles, constants and parameters. Some uppercase letters have separate names: \Gamma, \Delta, \Sigma and \Omega. A capital Latin-looking letter is often entered directly; there is no general rule that capitalizing any Greek command creates a valid uppercase command.

\alpha + \beta = \gamma,\qquad \Delta x = x_2-x_1

A command made of letters needs a boundary before ordinary letters. Write \alpha x or \alpha{}x for alpha followed by x; \alphax is a different, unsupported command. A space after a command name separates its spelling and is not usually a visible mathematical space.

Relations are different from operations

Use \leq and \geq to compare values, \neq for inequality and \approx for approximation. Use \times or \cdot for multiplication. An ordinary x represents a variable; it is not a substitute for the multiplication symbol in source.

a \leq b,\quad a \neq c,\quad x \approx y,\quad a \times b = ab

The toolbar’s Essentials category covers these common choices. Selecting one inserts its command at the cursor; it does not replace the rest of the equation.

Membership, subsets and number sets

\in says that an object belongs to a set. \subseteq compares two sets, allowing equality. \cup and \cap denote union and intersection. Write \mathbb{R} for the real numbers or \mathbb{N} for natural numbers; the braces identify the letter to style.

x \in A,\quad A \subseteq \mathbb{R},\quad A \cup B,\quad A \cap B

Membership and subset notation are not interchangeable: use the relation that matches the objects you mean. The editor typesets your choice but does not check whether the mathematical statement is true.

Choose an arrow for the relationship

\to is useful for a function’s domain and codomain or a limit. \mapsto describes the image of an individual input. \Rightarrow gives an implication arrow, while \Leftrightarrow gives a two-way implication arrow.

f:A \to B,\qquad x \mapsto f(x)

Named operators and large symbols

Commands such as \sin, \cos, \log and \lim use operator typography and spacing. Typing sin as plain letters instead makes it look like three variables.

\sin^2 x + \cos^2 x = 1

A summation uses _ for its lower limit and ^ for its upper limit. Put a multi-character limit in braces. In Display style, large operators have more room; Inline style uses a more compact layout.

\sum_{k=1}^{n} k = \frac{n(n+1)}{2}

If a symbol does not render

• Check spelling and capitalization, including the leading backslash.
• Check whether the command belongs to an extra package. The full MathJax command index includes extensions that MathTexLab does not load.
• Use the toolbar’s Greek, Arrows, Sets & logic or Operators category for an available command.
• Enter a mathematical expression without $ delimiters or a document preamble. MathTexLab is an equation editor, not a full LaTeX compiler.

Next, learn how braces group fraction arguments, or use these symbols inside a matrix.