# Question: Use the identity of Theoretical Exercise 5 to derive E X2

Use the identity of Theoretical Exercise 5 to derive E[X2] when X is an exponential random variable with parameter λ.

Theoretical Exercise 5

Use the result that, for a nonnegative random variable Y,

to show that, for a nonnegative random variable X,

and make the change of variables t = xn.

Theoretical Exercise 5

Use the result that, for a nonnegative random variable Y,

to show that, for a nonnegative random variable X,

and make the change of variables t = xn.

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