Recent content by rb120134

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    Studying Struggling with exercises after reading quantum mechanics textbook

    I just finished my three year bachelor degree in physics with an overall average grade of 7.4 on all courses. In september I will be starting my 2 year masters degree at University. I am reading through modern quantum mechanics third edition of J.J Sakurai and Napolitano. However, I do find I...
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    Normalizing the wave function of the electron in hydrogen

    Is it true that the probability of finding electron betwee r1= ao/2 and r2= 3a0/2 is 49,65%? For this problem
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    Show that the sum of the finite limits of these two series is also finite

    So let's say lim n> infity an =x then for every ε>0 there exists an N such that Ian-xI<ε for every n≥N. then if lim n> infity bn=y (where x and y are real numbers, given in question) for every epsilon greater then zero we can find an N such that I bn-yI<ε for every n≥N. we have Ian-x +bn-yI<ε...
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    Show that the sum of the finite limits of these two series is also finite

    In the homework I am asked to proof this, the hint says that I can use the triangle inequality. I was thinking that if both series go to a real number, a real number is just any number on the real number line, but how do I go from there,
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    Proof: Multiplication is commutative

    Thanks, but how do you deduce (n+1) x (m+1)=[(n+1) x m] + (n+1) I am stuck on the deducing part.
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    Proof: Multiplication is commutative

    How do you solve [ n++ x (m++) = (n++ x m) + n++ ], how can you show that this is the same? Source https://www.physicsforums.com/threads/proof-multiplication-is-commutative.782057/
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    Multiplication -- prove this one by induction

    Prove by induction that for any natural numbers n and m , n x (m++)= (n x m) + n The base case, n=0 gives 0 x m++=(0 x m) +0 gives 0=0 Now assume n x (m++) = (n x m) +n For n++ we get n++(m++)=((n++)m) + n++ from this point I am stuck, how can I prove both sides are the same?
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    Proving Limit Exists: x-2 of f(x)=2

    Given is the following: lim x-2 of f(x)=2 prove (using delta, epsilon definition of a limit) that a delta exists so that when [x]<delta then f(x)>1 I came up with when [x-a]<delta (f(a)-epsilon<f(x)< f(a) + epsilon) so f(a)-epsilon>1 so epsilon<f(a) -1 but I don't know how to prove this or...
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    What Does -∂V/∂x Represent in Newton's Law?

    In one of my textbooks about quantum mechanics, they mention a vehicle moving in a straight line along the x axis. With Newtons first law they take the second derivative from a which is d^2x/dt^2 and that should be equal to -∂V/∂x. What exactly does -∂V indicate? The complete equation...
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