A random sample of independent observations $x_{1}, x_{2},...,x_{n}$ of a distribution:
$f(x) = \theta^2x e^{- \theta x} $ with $0 \leq x < \infty$
consider $\hat{\theta}= \frac{2n-1}{\sum_{i=1}^n{X_{i}}}$ as an estimator for the parameter $\theta$ Consider the particular case of n = 1
1) Find $E(\hat{\theta})$
I most find $E$ of $(\frac{1}{x_{1}})$ but I really do not know how to do it Can anybody help me?