Recent content by wowowo2006

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    Completeness of basis in quantum mechanics

    In a QM course, I learn that an operator can be represented by basis vectors If the basis vector is complete, the following relation holds There exist coefficient Mij such that Sigma Mij |i > < j|. = I , |i> is the basis! and I is the identity matrix But isn't that in linear algebra We...
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    Problems about eigenvector in quantum mechanics

    So that means, When I change the basis, the matrix representation change So do the eigenvector changes too?
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    Problems about eigenvector in quantum mechanics

    I am learning about the basic quantum mechanics I know that an operator ,call it M^, is generally a matrix And we also can be represent it b a matrix representation M, associated with certain basis |e> M^ = sigma ( Mij |e> <e|) I,j Where Mij is matrix element of M So now I wonder...
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    Why we cannot solve quantum sho directly by fro envious series.

    I have just learned the quantum harmonic oscillator When we start to Solve the schodinger equation. y"= (K - x^2) y We look at large x behaviour and use a substitution y = u(x)* exp(-x^2 /2) to approximate the large x behaviour first, then we use series method to solve the equation...
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    Entropy change in isochoric process

    Homework Statement Hi everyone In an isochoric process ( a solid heat body with T1 temp. connected with heat bath with T2 temp) we could calculate its entropy change(heat body) from dS = Cv/T dT and entropy change of heat bath from dS = dQ / T2, using dQ = Cv dT in 1st equation ( i...
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    Proving partial deviatives not continous

    can someone offer help please?.
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    Proving partial deviatives not continous

    Homework Statement f(x,y) = y^2 + (x^3)*sin(1/x) when x =/= 0 = y^2 when x = 0 i want to prove fx(x,y) is not continuous at (0,0) Homework Equations The Attempt at a Solution i found when x=/=0 , fx = 3(x^2)sin(1/x) - xcos(1/x) -----eq(1)...
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    What is the Velocity of the Last Angstrom in the Falling Chain Problem?

    i know what you mean, you guide me to consider the motion of small portion of chain to obtain N1 = v * dm/dt but i still don't understand why the term m *dv/dt vanish even it should be in equation of Newton 2nd law
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    What is the Velocity of the Last Angstrom in the Falling Chain Problem?

    Homework Statement the question is about a very flexible strain falling on a rigid table and ask for expression of normal reaction of table at a certain instant Homework Equations when i was trying to solve problem , i resolve N(normal reaction) into N1, N2 which N2 is the weight of...
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    Some problems in electic field

    sorry i don't know what does 'The charges on the inner surface arrange themselves to cancel any field from the charge within the cavity' mean. does it mean that the e field within the cavity and the metal shell , both e field is zero or only with the shell. and why does the 'self arrangement of...
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    Some problems in electic field

    hey i got some problems in doing this question http://i4.photobucket.com/albums/y117/tkm20022001/AL%20PHY/phy03mc_32_33.jpg" the official ans is A i don't know why the 2nd statement is wrong. i think it's right as it;s at equilibrium state if not the charge will accelerate due to e field...
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