(五)How does Generative AI work, and what are the key technologies and major stages for developing Generative AI models? (5 分)

1. A couple has the same chance to give birth to a boy and a girl, and decides to have 3 children. If none of the 3 is a girl, they will try again; and if they still don't get a girl, they will try once more. If the random variable \( X \) denotes the number of children the couple will have following this scheme, then what is the expected value of \( X \)? (1)