I am not able to bring symbols "square root" and "theta" from mysql to html
HTML will not recognize those symbols unless they are converted to HTML Entities - notation like √ for the square root sign. You can convert to them from MySQL using PHPs htmlentities() function.
W3C HTML 5 entity reference: http://dev.w3.org/html5/html-author/charref
Overview of useful HTML entities: http://htmlentities.net/html/entities/