Promote the Use of Two-dimensional Continuous Random Variables Conditional Distribution

Conditional distribution reflects the dependency link among random variables, but two-dimensional random variables Conditional Distribution has some limitations. In order to rich the content of conditional distribution this paper gives the extension of conditional distribution and examples in the case of continuous random variables. For the given definition of conditional distribution of three-dimensional continuous random variables, it also gives the proof. This article obtains the extension strictly in accordance with the definition of two-dimensional random variables and it uses the theory of conditional probability to get the proof. So it can get conditional distributions after changing the condition to enrich the contents of the conditional distribution.