\usepackage{mathtools}
\DeclarePairedDelimiter{\ceil}{\lceil}{\rceil}
The command \ceil will do; if called as \ceil*{x} it will add \left and \right; you can also call it as
\ceil[\big]{x} \ceil[\Big]{x} \ceil[\bigg]{x} \ceil[\Bigg]{x}
to state explicitly the size of the delimiters.
Answer from egreg on Stack Exchange\usepackage{mathtools}
\DeclarePairedDelimiter{\ceil}{\lceil}{\rceil}
The command \ceil will do; if called as \ceil*{x} it will add \left and \right; you can also call it as
\ceil[\big]{x} \ceil[\Big]{x} \ceil[\bigg]{x} \ceil[\Bigg]{x}
to state explicitly the size of the delimiters.
Here is a simple xparse implementation of \ceil, similar to that provided by mathtools' \DeclarePairedDelimiter:
\documentclass{article}
\usepackage{xparse}% http://ctan.org/pkg/xparse
\NewDocumentCommand{\ceil}{s O{} m}{%
\IfBooleanTF{#1} % starred
{\left\lceil#3\right\rceil} % \ceil*[..]{..}
{#2\lceil#3#2\rceil} % \ceil[..]{..}
}
\begin{document}
\[\ceil[\big]{x} \quad \ceil[\Big]{x} \quad \ceil[\bigg]{x} \quad \ceil[\Bigg]{x} \quad \ceil*[\big]{\frac{1}{2}}\]
\end{document}
The optional argument is ignored in the starred version of \ceil*[..]{..}.
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Using \DeclarePairedDelimiter from mathtools, you could define macros \ceil and \floor, which will scale the delimiters properly (if starred):
\documentclass{minimal}
\usepackage{mathtools}
\DeclarePairedDelimiter\ceil{\lceil}{\rceil}
\DeclarePairedDelimiter\floor{\lfloor}{\rfloor}
\begin{document}
\begin{equation*}
\floor*{\frac{x}{2}} \leq \frac{x}{2} \leq \ceil*{\frac{x}{2}}
\end{equation*}
\end{document}
Result:
You can define your own macro via the
\defcommand anywhere in your document. For example\def\lc{\left\lceil} \def\rc{\right\rceil}and then just write
\lc x \rc.Or you use the
\providecommandin the preamble, e.g.\providecommand{\myceil}[1]{\left \lceil #1 \right \rceil }to simply use
\myceil{x}in your document.- Use an editor, like vim, that allows for defining shortcuts for quick and efficient editing.
- And, finally, don't forget about readability of your tex document. Check out this thread for some instructive comments on how to write efficient and readable tex math docs.
Your function scales both input 
and output 
up by a factor of 
:
$$
\lfloor 100 x \rfloor = 100y,
$$
i.e. if we define these scaled coordinates $X = 100x$ and $Y = 100y$, then the equation relating inputs to outputs looks like
which you can think of the prototype of the relationship between the variables. Putting all the transformations in one diagram looks like
so the only way to build the composition 
is to invert that last arrow 
to produce 
, namely to divide by the scaling factor, hence we introduce fractions.
As always, we can hide the fraction inside of a definition, which doesn't change the fact that we're dividing by the scaling factor, but cosmetically, it might look nicer. We could, for instance, for any 
, define a rounding function with precision 
by
that has the property that 
for all 
. With this notation, your example would look like
You are asking about truncation.
In the linked Wikipedia article, the notation is as follows.
Given a number 
to be truncated
and 
, the number of digits to be kept after the decimal point,
the truncated value of 
is
$\operatorname {trunc} (x,n)={\dfrac {\lfloor 10^{n}\cdot x\rfloor }{10^{n}}}$.
You should read some guides (starter guides) for LaTeX and math (especially about the sizes). With the knowledge about them you could easily adapt to this (\bigg):
\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{mathtools}
\DeclarePairedDelimiter{\ceil}{\lceil}{\rceil}
\begin{document}
\begin{equation}
\ceil[\bigg]{\frac{\log{(1-P_{0})}}{\log{(1-p)}}}
\end{equation}
\end{document}
Very simple, you can work with the asterisk.
\documentclass{memoir}
\usepackage{amsmath,amsfonts,amssymb}
\usepackage{mathtools}
\DeclarePairedDelimiter{\ceil}{\lceil}{\rceil}
\begin{document}
\begin{align}
\ceil*{\frac{\log (1-P_{0})}{\log (1-p)}}
\end{align}
\end{document}
I also applied some minor improvements on log vs \log.
Please consider the manual http://www.ctan.org/pkg/mathtools .
Just for adding some informal tags: Kenneth Eugene Iverson floor ceiling notation.
I want to paint my bedroom ceiling and give it a nice new fresh cost of paint. I have white Latex based ceiling paint I want to use but im unsure of what kind of paint is on the ceiling now. Am I good to slap a coat of this latex based ceiling paint on my ceiling? Will it adhere?