There are different ways of accssing help in Matlab environment.
If you know the name of a Matlab function you need help with, type
>> help plot
>> help control
to see the "helpful" information contained in the function definition itself. Search is very slow, and often deluges the user with a great many unhelpful items. In addition, a search for a concept, such as "matrix" will almost never return what you need.
You can get the same "helpful" information by choosing Help -> Help Window, or typing;
A more useful (but more difficult to access) set of help files is included in HTML. To access it, choose Help->Help Desk, or type;
This will launch your system's default web browser and open a web page.
While the content is essentially the same as the built-in help, it is presented in a much less hostile format. The Java-based full-text search and index-by-subject are two extremely useful features. In addition, the entire set of printed manuals is available as Adobe PDF documents.