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指数随机变量的期望:计算 E[X] = integrate from 0 to infinity of x lambda e^(-lambda x) dx 并证明结果为 1/lambda 。
指数随机变量的期望:计算 E[X] = integrate from 0 to infinity of x lambda e^(-lambda x) dx 并证明结果为 1/lambda 。
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