Request.IsAuthenticated is always false

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MVC4

Hello,
I am a beginner in MVC and is working on an application which integrates all social networks(Facebook, Twitter, LinkedIn) within it. All works fine but am getting Request.IsAuthenticated as false always even if i am setting cookie using
FormsAuthentication.SetAuthCookie(value, boolena value)
I am running this application under VS2012 and also using DotNetOpenAuth. I guess this is the point where I am getting stuck but need a little more guidance over it.
Can it be explained and rectified? I need to check Request.IsAuthenticated since I am toggling Log in and log off links on master page.
Please help me out.
Thanks in advance,
Nutan Ranee,
Pune