Homework Help: Expectation value of x

1. Aug 2, 2007

ehrenfest

I am trying to find <x> for

$$\psi(x,t) = A exp\left(-|x|/L - i*E*t/\hbar\right)$$

I found the normalization factor of 1/L and I took

$$\int_{-\infty}^{\infty}\left( x * exp(|x|/L) \right)$$ in two

integrals however I got as a final result:

$$L * -\infty * exp(-\infty/ L) - L * \infty * exp( - \infty /L)$$

Is that 0?

2. Aug 2, 2007

Sojourner01

$$L * -\infty * exp(-\infty/ L) - L * \infty * exp( - \infty /L) = -2 * L * \infty * exp(-\infty/ L) -> -\infty/exp(\infty) -> 0$$