change space to only a part of the document [duplicate]

Question

Possible Duplicate:
Change line spacing of a page and size police inside the document

I created a document using book class and set the space using

\usepackage{setspace} 
\onehalfspacing

In this way all my document use this setting.

Instead I would know how I change space to \doublespacing to only a part of my document.

Answer 1

You could type \begin{doublespacing} and \end{doublespacing} at that beginning and at the end of the part of your document that you want to be double-spaced.

Answer 2

You can use them inside a group:

\documentclass{article}
\usepackage{setspace,lipsum}
\begin{document}
\onehalfspacing
 \lipsum[1]
\bgroup %% <<<<<<< begin a group
\doublespacing
\lipsum[2]
\egroup %% <<<<<<< end a group
{   %% <<<<<<< begin a group
\singlespacing
\lipsum[3]
} %% <<<<<<< end a group
\end{document}