EM算法是人工智能十大算法之一。三硬币模型算例出自李航的《统计学习方法》，书中给出了计算结果和简单解说，对于不是学数学的看这种复杂的公式看不懂，我也看了很久才看懂。我用matlab编写的代码，并作了详细的注释。(EM algorithm is one of the ten major algorithms of artificial intelligence. The three coin model is derived from Li Hang's statistical learning method. In the book, the calculation results and simple commentary are given. For those who do not learn mathematics, they can not clearly understand this complicated formula. I have seen it for a long time,too. I used MATLAB language wrrting the source code in　and annotated it in detail.)