Why did macbeth kill king duncan?

Why did Macbeth Kill King Duncan?

At the beginning of the play Macbeth the main character is portrayed as a brave and noble character that is both loyal and valuable to his King. In this play the transformation of the main character is outstanding as he completely changes from worthy nobleman to a murdering traitor.
Ultimately Macbeth was not alone in his terrible deed, he was pushed and persuaded by other characters including his wife, Lady Macbeth.
Also the three witches have great responsibility over the deed, as it is they who plant the idea of being King inside his head. However the reader becomes aware that this isn’t the first time Macbeth has thought about becoming King
Over 7 short Scenes there is a Dramatic change in the Character of Macbeth

In act one the reader (or audience) finds out how Shakespeare categorizes the characteristics of men and women of this time. Men are valiant, cunning, knowledgeable and fearless. Women are supposed to be delicate, dainty and ...