Who read Hamlet help me please: Hamlet claims that his madness

Hamlet claims that his madness is feigned, an “antic disposition” which he puts on for his own purposes (I.v.172).  Why would Hamlet want to feign madness?  How can an appearance of insanity help him achieve his ends?  Is he really sane throughout the play, or does he ever cross the line into madness? What about Ophelia’s mad scene?  Is it real or feigned?  Is there “method in her madness” as well , or is she entirely irrational?  Why has she gone mad?