Math Test

1 Limit

A limit:
limx → ∞f(x), 
which should appear as x → ∞ in italics, and «lim» in plain style. Inlined: limx → ∞f(x).
And why not, a sum:
i = 1x, 
where the sum’s limits should appear below (i = 1) and above () the but to the right. Inlined: i = 1x. Integral: i = 1x.
A sum inside another element (red color):
i = 1x.
When any element has both super- and subscript, they should appear like inlined limits, one above the other: a34. Also before an element: 32 He. In display mode:
i, jaij + i, jaji = iaii, 
21 H + 21 H → 32 He + 10 n.

2 Numeration

Equations can be numbered, like 1↓.
(1) y = x
And also like 2↓.
(2) x = 3
Notice that eq. 2↑ comes after eq. 1↑.
Some equations can also be numbered, even if they don’t have a label.
(3) x = 2y
Other equations that contain * should not numbered, but perhaps aligned:
left right
Some environments allow for multiple labels:
(4) (5)
a  =  b × c
c × d × e  =  i.
Now a random environment:
x
y
.

3 Parentheses

Some delimiters also taken from the Spanish Lyx User’s Guide. An array:
[
12 2
3 4 × yx
]
And an inline array [
a b
c dio
]
.
There are also big brackets: (a) [b] {c} d |e| f.
Aligned brackets can be present: (toText). One of them may be omitted: toText).

4 Fraction

A big recursive fraction:
1(1 + (11 + (11 + 2x)))
A nice fraction: 56.
A non-diminishing fraction containing alignments:
11 + (11 + x × 11 + x).
A similar concept is a binomial coefficient: (A + 1B). It can be prettily presented:
(AB + 1).
A symbol can be stacked over another using \stackrel: xR → y. Anything can be stacked: headheels.

5 Roots

A square root: 3. A more complex square root in a fraction:
1(1 + 2(11 + 2) + 12).
Higher order roots: 3x + y, x + 1Weight. In a fraction:
7884xs + 5(78x + 45y) × Heightsin(x + 1) + 5.

6 Decorations

6.1 Cases

Used to switch several values.
y = 
x i = 0, 
x + 1 i < 3

6.2 Braces

Values can be underbraced or overbraced.
a − b = c + d + e + f.
Underbraces and overbraces can contain text.
a − bover = c + d + eover + funder + g.
They can also be inlined: a + bover.

7 Spacing

The command \raisebox is useful to, surprisingly, raise a little box.
raisedoverloweredand back.
It can also be used just for spacing.
BV.
There are other spacing commands, like \hspace: " ", and \vspace: " ". Protected space can be used: a b.

8 Fonts

Fonts can be switched on and off.
By default, text in formulae is shown italicized. Variable: meters.
Some font styles. Roman: 1 mathrm. Sans serif: 2 mathsf. Typewriter: 3 mathtt. Bold: 4 mathbf.
Regular text. Normal text: 5 textfm. Literal text: 6 mbox text. Phonetic alphabet: 7abcde. Regular text can be embedded into formulae: regular text \command \another command \\no spaces allowed.
Units can be shown with or without a magnitude. Without: km. With: 57 km. Fractional units: 20 kmh. With a fraction before the units: 32 km, 716 s.
Some special fonts are supported: , F, 𝔽, 𝔉.
There has been some trouble over some commands like Greek letters; some of them should be italicized, as in: μ or Å. Others should not, as in Ω.

9 Colors and Boxes

A colored box: aaa.
A framed box: box. It can be aligned left: box or right: box.

10 Macros

Definitions can be added as macros. Then they can be used in formulae: 12 + 12. They can accept default parameters. Again, useful in formulae: 45.
Other definitions from the preamble can be used: 34.
Definitions on the fly are also possible: 78, and used with different values: ab.

11 Pathological Cases

Empty equations have been known to fail: .
An equation with an mbox containing a comment: text more, and a comment inside textrm: text more. Finally, a comment at the end of a text function: only text.

12 Bye-bye

That’s all folks!