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peace

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hi. How to obtain the expected value of x in the momentum space ?

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In summary, the conversation is about obtaining the expected value of x in the momentum space. The person asking the question has the result but is looking for a complete solution. They are advised to check their textbook or search online for a derivation. A helpful link is provided for reference.

- #1

peace

- 44

- 4

hi. How to obtain the expected value of x in the momentum space ?

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Looks like you have answered your own question.

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peace

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I only have the result. But I don't have the perfect solution to tell me how to achieve that. I'm looking for a solution.PeroK said:Looks like you have answered your own question.

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peace said:I only have the result. But I don't have the perfect solution to tell me how to achieve that. I'm looking for a solution.

Whatever textbook you are learning QM from ought to have a derivation. If not, you should be able to find one online.

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peace

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In my textbook only the result has been written, and not the complete solution.PeroK said:Whatever textbook you are learning QM from ought to have a derivation. If not, you should be able to find one online.

Yet, yes, you are right. I search for a complete solution online.

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There's one here, for example.peace said:In my textbook only the result has been written, and not the complete solution.

Yet, yes, you are right. I search for a complete solution online.

https://physics.stackexchange.com/q...-the-momentum-representation-from-knowing-the

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peace

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thank you very much for your search for me.PeroK said:There's one here, for example.

https://physics.stackexchange.com/q...-the-momentum-representation-from-knowing-the

The expected value, also known as the mean, is a measure of central tendency in a probability distribution. It represents the average value of a random variable X, taking into account all possible outcomes of X and their associated probabilities.

The expected value of X is calculated by multiplying each possible outcome of X by its respective probability and then summing all of these products together. This can be represented mathematically as E(X) = Σ x * P(x), where x is a possible outcome of X and P(x) is the probability of that outcome occurring.

The expected value is important because it provides a single numerical value that summarizes the entire probability distribution of a random variable. It can also be used to make predictions about future outcomes and to compare different distributions.

The expected value is a theoretical value based on probabilities, while the actual value is the observed or measured value. The expected value may not always match the actual value, as it is an average of all possible outcomes, whereas the actual value is a specific result.

Yes, the expected value can be negative if the probabilities associated with the possible outcomes of X are negative. This can occur in situations where there is a chance of incurring a loss or negative outcome. However, the expected value can also be interpreted as a measure of average gain or loss, so a negative value may still be meaningful in certain contexts.

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