What is Macbeth's reaction when Duncan tells him that he is planning to have his son, Malcolm, be named the Prince of Cumberland and the heir to the throne?

Macbeth (now also named the Thane of Cawdor) is starting to believe the witches earlier prediction. The witches predicted that he would be Thane of Glamis, Thane of Cawdor, and the king of Scotland. Since two of the three come true, he believes it's a possibility that he could be king. However, when King Duncan names Malcolm as his successor, Macbeth becomes upset.