There are three main ways you can write mathematical expressions to make sure they can be read by others:

• plain text: use strictly keyboard characters, all inline
• rich text: use formatting with superscripts, subscripts, and other tools on the tool bar
• LaTeX (pronounced "lah-tech"): a special formatting code used by mathematicians

We do not yet directly support LaTeX formatting (but see below), and even when we do, it will often be more convenient to use plain text or rich text conventions instead, because we do not provide a way to preview and correct your formula. Here are the essentials:

If you want to format an expression across multiple lines (as in the fraction examples below), you should choose a fixed-width font (Courier New) for that part of your message, and use SHIFT-ENTER instead of ENTER to move to a new line (avoiding extra spacing). Use the space bar to line up text, NOT the tab key. Often an expression can be typed all on one line, making it a little harder to read, but easier to type.

To type special characters such as π, ≤, √, and ∫, use the button labeled Ω on the tool bar.

Fractions may be typed using plain text in multi-line or single-line format:

  a)    1           b) 1/(2x)
       --
       2x

In the latter form, use parentheses generously; if you type

  c) 1/2x

it might be read as either  1/(2x), "1 over 2x" or as (1/2)x, "one half x". Parentheses prevent misunderstandings.

Exponents can be represented either using rich text superscripts like x² + x⁵ⁿ, or using "^" (both in plain text and in LaTeX): 

  a)   2    5n      b) x^2 + x^(5n)  or  x^2 + x^{5n}
      x  + x

Use parentheses or braces to make it clear what is the base and what is the exponent in the last form.

Subscripts can be represented using rich text subscripts, as p₁ = "p sub 1", or in plain text as p_1, p[1], or p_{1}; the latter two forms are needed when the subscript is an expression rather than a single number (the last is used in LaTeX). But it is often clear enough to just write p1. On the other hand, subscripts are easy enough to use on this site.

Square and Cube Roots can be written using the special character button, labelled Ω, to enter the square root symbol, √; or in plain text as sqrt(x) and cbrt(x), or as x^(1/2) and x^(1/3). 

But be careful: there is no vinculum (overbar) in rich text, so if more than one number is inside the radical, use parentheses around the radicand. And for a cube root, the 3 must be written as a superscript. Here is an example:

  write ³√(x + y), not 3√x + y

Always be careful to use enough parentheses to make your meaning clear!

One (indirect) way to get LaTeX equations into what you write in the Doctor's Office is to go to CodeCogs, where you can edit an equation until it looks right, then right-click on the image of the equation and select Copy image address, then use the Insert/Edit Image icon on the toolbar and paste in that address. Here is a typical result:

For more ideas, see Formatting Math as Text, and Typing Math.