AUCTeX is an extensible package for writing and formatting TeX files in GNU Emacs and XEmacs. It supports many different TEX macro packages, including AMS-TEX, LaTeX, Texinfo, ConTEXt, and docTeX (dtx files). AUCTeX includes preview-latex which makes LaTeX a tightly integrated component of your editing workflow by visualizing selected source chunks (such as single formulas or graphics) directly as images in the source buffer.
(add-to-list 'load-path "~/.emacs.d/auctex") (load "auctex.el" nil t t) (load "preview-latex.el" nil t t)
(setq TeX-PDF-mode t)
Configure view program
(setq TeX-view-program-selection '((output-dvi "DVI Viewer") (output-pdf "PDF Viewer") (output-html "HTML Viewer"))) ;; this example is good for OS X only (setq TeX-view-program-list '(("DVI Viewer" "open %o") ("PDF Viewer" "open %o") ("HTML Viewer" "open %o")))