How to control the variable in emacs?

The page 49 of org mode manual has the following comment.

"To limit tag inheritance to specific 开发者_JAVA百科tags, or to turn it off entirely, use the variable org-use-tag-iheritance and org-tags-exclude-from-inheritance." 

It seems that I should set those variables to 1 or t inside emacs. Is this correct? If so, how can I do that?

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M-x set-variable RET var RET value (from http://www.delorie.com/gnu/docs/emacs/emacs_478.html)

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To configure these permanently, you can use (setq variable value) in your .emacs file. Alternatively, as these variables are both defined with defcustom, you can also use:

M-x customize-variable org-use-tag-iheritance
and M-x customize-variable org-tags-exclude-from-inheritance

to configure them either temporarily or permanently.