% All commands which have more than one argument 
% can be used in the following three ways:

\begin{bf}
Some text.
\end{bf}

\bf{Some text.}

{\bf Some text.}

% With the third method, it is important that the 
% command has its own pair of braces, and that 
% the command immediately follows the first brace. 
% Otherwise, the parser cannot parse the argument(s) 
% properly. With multiple arguments, 
% each should be enclosed in braces.
% Optional arguments are specified using square brackets or parentheses.
% Whitespace should be avoided between command names and their arguments.

% A mathematical formula:
\begin{split}
  Q &= \int_{\nu} \rho_{\nu}\, d \nu \\
    &= \int_0^4 \int_0^{\frac{\pi}{2}} \int_0^2 3(z+1) \cos \phi \, d\rho \, d\phi \, dz \, \mu C \\
    &= \int_0^4 \int_0^{\frac{\pi}{2}} 6 (z+1) \cos \phi \,d\phi \,dz \,\mu C \\
    &= \int_0^4 6 (z+1) \,dz \,\mu C \\
    &= \frac{6z^2}{2} + 6z \Bigg|_0^4 \,\mu C \\
    &= 3(16) + 6(4) \,\mu C \\
    &= 72 \,\mu C
\end{split}
  
% Nested commands:
{\em This sentence is {\em emphasized}, with emphasis on the word {\em emphasized}.}