Math looks so pretty, all nicely formatted in the
textbook. But when you go to e-mail your instructor with a question, or post your question to a
math tutoring forum, you can end up with a mess or with something that totally doesn't mean what
you meant it to mean. To deal with this issue, the math community is developing norms for text-only
formatting. What follows is not "the" one right way to format math, but is a distillation
of what I've seen a lot of math tutors use.
Type-set formatting
Text-only formatting
Notes
4 ÷ 2
4/2 4 ÷ 2
The "slash" is commonly used to indicate division
or fractions, but you can also insert the "divided by" sign (on a PC) by holding
down the "ALT" key and typing "0247" on the numeric keypad.
4 × 2
4 * 2 4 × 2 (4)(2)
The asterisk is commonly used to indicate multiplication,
but you can insert the "times" sign (on a PC) by holding down the "ALT"
key and typing "0215" on the numeric keypad.
(1/2)x + 5
Without the parentheses around the "one-half", it
will be unclear whether or not the variable is meant to be included in the denominator.
1/(2x) + 5
The variable isn't often in the denominator like this, so
use parentheses to make it clear where the variable belongs.
1/(2x + 5)
The parentheses make it clear that the "five" is
included in the denominator.
Without the parentheses, it would not be clear that the first
"x" belongs inside the numerator, or that the "5x + 6" belongs inside
the denominator.
(x + 2)/(x^2 + 5x + 6)
Use different grouping symbols to demark the two fractions
within the complex fraction. Using extra spaces is helpful, too.
[(x + 3)/5] / [(x - 4)/2]
x2
x^2
The carat key, usually "shift-6" on the keyboard,
is customarily used to indicate exponents.
x^(2/3)
Without the parentheses, it will look like you mean "x
squared, divided by three".
23x
2^(3x)
Without the parentheses, it will look like you mean "two
cubed, times x",
when you actually mean the variable to be in the exponent.
x2y3z4
x^2 y^3 z^4
Use spacing to make clear where one factor (and its exponent)
ends and the next begins.
f–1(x)
f^(-1)(x)
Yes, this is clunky notation, but the tutors will understand
that you mean "f-inverse
of x."
(f o g)(x) f(g(x))
Either use a lower-case O to indicate function composition,
spacing things out so it doesn't look like you're trying to spell "fog", or else
switch from "f-compose-g of x" notation to "f of g of x" notation.
Piecewise functions are one of the few items for which multi-line
formatting is pretty-much inescapable. Just do the best you can.
The abbreviation "sqrt" stands for "the square
root of", and the parentheses make it clear that both the "two" and the "y"
belong inside the radical.
cbrt(7)x
The abbreviation "cbrt" stands for "the cube
root of", and the parentheses make it clear that the "seven" is inside the
radical, but the "x" is not.
5th-rt(z)
For larger-index roots, give the value of the index, and explain
your notation. In this case, you would say "I'm using '5th-rt()' to stand for 'the fifth
root of' z."
>=
Write out "greater than or equal to" just as you
say it: a "greater than" sign followed by an "equals" sign.
<=
Write out "less than or equal to" just as you say
it: a "less than" sign followed by an "equals" sign.
~ = (approx)
The "wiggly equals" means "approximately equal
to", and indicates that you've rounded. You can either use the tilde (the single wiggly
line, probably close to the "ESC" key) or a regular "equals" sign followed
by the notation "(approx)", indicating that the answer is an approximate value.
If you use the tilde, say what you mean by it.
!= =/= <>
The exclamation mark is commonly used in computer programming
to mean "not", so "!=" means "not equal". But the "equals-slash-equals"
sequence more closely simulates the "not equal to" symbol. The "less than,
greater than" sign is also sometimes used, but not so commonly. Whichever you use, define
in your post what you mean by the notation.
±
+/- ±
You can use "+/–", or you can enter the character
directly (on a PC) by holding down the "ALT" key and typing "0177" on
the numeric keypad.
x1
x1 x_1 x[1]
Subscripting doesn't come up much, and it's a pain when it
does. Many people just put the subscript after the variable, but this can be confused with
superscripting. The underscore is handy, but if you're dealing with very complicated expressions,
you might want to use the bracketing notation. Define what you mean ("x-sub-one")
in your post.
log2(5)
log_2(5)
Use the underscore to indicate the base, and use parentheses
to make clear what is inside the log.
ln(x)
ln(x)
Do not use a capital "I"
for the natural log. The notation is "LN", not "IN". And don't forget
your parentheses.
log(y)
log_2(y) log_10(y) log_e(y)
If you use just plain "log(y)", the base will be
unclear. Either use the underscore notation to state the base, or else define yourself. Depending
on the context, a plain "log", without a base noted, will be assumed to have a
base of 2, of 10, or of e. Don't assume the tutor knows which one you mean.
log2(4)
log^2(4) [log(4)]^2
The square can go right on the function, but this can sometimes
get a bit confusing, especially if your log has a base notation on it. In messy cases, put
the exponent outside the function, using brackets (so the power goes on the log, and not
just the argument).
|–6|
|-6| abs(-6)
You can use "abs()" to indicate absolute value (or
"modulus"). But you should be able to enter the absolute bars into your post by
using the "pipe" character. Look for a key somewhere above the "Enter"
key with a shift character that looks like a broken line. It will type as a solid line.
If you must use multi-line formatting (rather than
the single-line formatting demonstrated above), then use especial care in formatting. (This would
apply to such things as polynomial long division or synthetic division.) If you're e-mailing your
question, then compose the post using a fixed-width font such as Courier, and warn the recipient
that he'll need to view the post in a fixed-width font. If you're posting to a message board, use
"PRE" tags, if allowed, or else format using the "CODE" tags (or something
similar). And remember to "Preview" your post before actually posting it to the message
board, so you can make sure that your post clearly says what you mean it to say.
Use standard abbreviations, or none at all. For
instance, "m" means "meters" (though it could also, depending on the context,
mean "slope"); if you mean "miles", use "mi". If you're not sure
of the abbreviation, spell it out; if you want to invent your own abbreviation, that's find, but
define yourself clearly. For instance, if you're working with rational expressions, don't just
say "i cant find HA"; instead, say "I'm having trouble finding the horizontal asymptote
(HA)".
One note on variables: Don't change the case in
the middle of your post. In math, a capital "X"
and a lower-case "x"
are not the same thing. If you change, willy-nilly, back and forth between cases, you'll have the
tutor wondering if you really mean two different variables. If you mean only one variable, then
use only one name for it.
Stapel, Elizabeth. "Formatting Math as
Text: Common Algebra Notation." Purplemath. Available
from http://www.purplemath.com/modules/mathtext.htm.
Accessed
![[(x + 3)/5] / [(x - 4)/2]](format/format13.gif){kind=small}
