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Typing Math

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How can I type exponents? What about square roots? Why shouldn't I ever use tabs? May I send attachments? Etc.
When you send Dr. Math a question, you must work just within the text entry boxes on our submission page. You will need to type any math that appears in your question using only the standard keyboard character set.
We do not currently offer a way for you to submit attachments, e.g., Word or Excel files, graphic images, and so on. If you can arrange to put such a document on a web server somewhere, you can include the URL in your question. However, finding and opening these documents takes time, so your chances of getting the attention of one of our volunteers increase if you can say everything you need to say using only text.
So how do we "type math"? Here are some guidelines:

Don't use tabs!
Good math notation is mostly a matter of spacing, especially when (as in the example below) your expression takes up more than one line of text. It's important to use the space bar to line up text, NOT the tab key; since the number of spaces equal to one tab varies from computer to computer, what might look right to you could be way off the screen for someone else, and
THIS (with spaces) might look like THIS (with tabs) 347 347 --------- ---------- 100 ) 34700 100 ) 34700 300 300 --- --- 470 470 400 400 --- --- 700 700

Fractions
There are a couple of acceptable options for the fraction "1 over 2x":
a) 1 b) 1/(2x) -- 2x
Both (a) and b) are correct, but because (b) sits on a single line of text, it's easier to work with if you want to include the notation within the body of a paragraph. When you write fractions like the one in (b), however, you must be careful to put parentheses in the right place. Here's an example of what can go wrong:
c) 1/2x DON'T DO THIS!
Don't write fractions like the example in (c)! You might mean "1 over 2x" but (c) could also be interpreted as "one half x" - and these are not the same. Note: brackets can be used in lieu of parentheses.

Exponents
How should you represent "x squared plus x to the 5y-th power"? Here are two correct ways:
a) 2 5y b) x^2 + x^(5y) x + x
Again, if you decide to write the entire expression on one line as in (b) -- which is often preferable -- and you foresee any possible confusion over the exponent, you MUST use parentheses to set off the exponent. [Note: For a complex discussion of language and mathematical notation, see Exponents and Negative Numbers; for examples of how to write large numbers in base 10 using exponents, see Scientific Notation.]

Subscripts
The most standard way to write p sub 1 (p₁) is p_1. However, it is rarely necessary that 1 be understood as a subscript. In e-mail we can usually just write p1 where on paper we would write a subscript to provide a nice naming scheme for a list of variables. Of course, there are exceptions when a subscript actually has meaning, just as x^2 has meaning and is not simply a label.

Square and Cube Roots

"The square root of x" can be written sqrt(x).

Since there's no easy way to write cube root symbols (and higher), it's best to express your root as a power. "The cube root of seven" can be written 7^(1/3).

In general, you will be able to write any root using your keyboard if you remember that

On the blackboard:
On your keyboard:
sqrt(2)/2
Sqrt(2) sqrt(2)/2 or ------- 2

(pi)r^2
2 (pi)r^2 or pi*r^2 or (pi)r

x less than or equal to 0
x <= 0

x goes to infinity
x --> infinity or x --> infty

((A+X)/2 , (B+Y)/2)
/ A+X B+Y \ ( ----- , ----- ) or ((A+X)/2 , (B+Y)/2) \ 2 2 /

$sum_{k=0}^{s-1} {n choose k}$
s-1 n Sum ( ) or sum_{k=0}^{s-1} {n choose k} k=0 k

INT[(4-x^2)dx] from -2 to +2
INT[(4-x^2)dx] from -2 to +2

On the Web

Typesetting, from Principia Hypertextica - A Mathematics Educator's View of Web Design, by William I. Johnston.

On to Typing Pictures

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