How can I find the square of expectation value for a particle in a box?

In summary, the square of expectation value is a mathematical concept used in statistics and probability theory to represent the expected value of the squared deviations from the mean of a random variable. It is calculated by squaring the mean or average value of the variable and is important in understanding its variability. The square of expectation value cannot be negative and is directly related to the variance of the variable through the variance formula.
  • #1
ghallya
16
0
hi all

can sombody show me the way I could get
the square expectation value http://06.up.c-ar.net/03/fd4f.jpg for a particle in a box

where the answer is given to us :
http://06.up.c-ar.net/03/87d0.jpg
 
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  • #2
[tex]<x^2> = \int {\psi^*(x) x^2 \psi(x)dx}[/tex]

For the limits of integration, use the positions of the ends of the box. Some books use a box with 0 < x < L, others use -L/2 < x < +L/2, with correspondingly different wavefunctions.
 
  • #3
jtbell said:
[tex]<x^2> = \int {\psi^*(x) x^2 \psi(x)dx}[/tex]
Where psi is orthonormal.
 

What is the square of expectation value?

The square of expectation value is a mathematical concept used in statistics and probability theory. It is the square of the mean or average value of a random variable. It represents the expected value of the squared deviations from the mean.

How is the square of expectation value calculated?

The square of expectation value is calculated by taking the mean or average value of a random variable and then squaring it. This can be represented as (E[X])^2, where E[X] is the expectation value of the random variable X.

What is the significance of the square of expectation value?

The square of expectation value is important in understanding the variability or spread of a random variable. It provides a measure of dispersion from the mean and is used in various statistical models and calculations.

Can the square of expectation value be negative?

No, the square of expectation value cannot be negative. It is always a positive value because it represents the squared deviations from the mean, which cannot be negative.

How is the square of expectation value related to the variance?

The square of expectation value is directly related to the variance of a random variable. In fact, the variance is equal to the square of expectation value minus the expectation value of the squared variable, or Var(X) = E[X^2] - (E[X])^2. This relationship is known as the variance formula.

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