Prove Uncertainity Relation for Particle in a Box w/ Length L

[string_theory]

Hi dear virtual friends,

I am now going to ask you something. I would be pleased if you would answer me.

In an exam I was asked to show that for a particle in a box of width length L , delta (x)delta(p)>=h/(4*pi) holds.
I think this is not a logical question. Because I think it is like asking something like this: Prove A using A.

I would be really grateful if you would write something regarding this.
Thank you.

P.S. My problem is not envolving you in doing my homework. I just wanted to know if what I think is right or wrong.

 

[lethe]

i think you were supposed to calculate Δx and Δp separately, then multiply the two together, and compare it to h/4pi.

you know, find the expectation value of x, and then the expectation value of x² and all that jazz.

of course you are not allowed to use the Heisenberg Uncertainty principle to show that the Heisenberg Uncertainty principle is true. that is circular.

 

[string_theory]

Thank you very much for youranswer.