Intereting Posts

elementary ways to show $\zeta(-1) = -1/12$
A morphism of free modules that is an isomorphism upon dualization.
My proof of $I \otimes N \cong IN$ is clearly wrong, but where have I gone wrong?
Does this inequality involving differences between powers hold on a particular range?
Prove that N with its usual metric inherited from R is a discrete metric space
Is a complex number with transcendental imaginary part, transcendental?
A specific 1st order PDE which looks almost like a linear PDE
Every Cauchy sequence in $\mathbb{C}$ is bounded
Evaluate $\int\frac{d\theta}{1+x\sin^2(\theta)}$
How to find out which number is larger without a calculator?
Evaluating $\int \sqrt{x^2-3}\:dx$
Canonical example of a cosheaf
For integers $a\ge b\ge 2$, is $f(a,b) = a^b + b^a$ injective?
Bounds on roots of polynomials
Finding the Fourier series of a piecewise function

While doing a calculation in quantum mechanics, I got a expression $\sin(\omega t)$, and my prof said if I consider the consider at large times, then i can assume that this goes to zero because at large times, the graph of $\sin$ oscillates very rapidly and so you can take it to be zero. When i asked about this he said we want to check for $\frac{\Delta t}{t}$(no units) which should be invariant, and so at large times, we need to take long time(means many cycles) for same ration of $\frac{\Delta t}{t}$.

But I wasn’t convinced by this explanation. I want to know is this mathematically consistent.

- Two different expansions of $\frac{z}{1-z}$
- Looking for a Simple Argument for “Integral Curve Starting at A Singular Point is Constant”
- For any subset $S$ of $\mathbb{R}$, the distance function $d_s(x) = d(x,S)$ is continuous
- Why are gauge integrals not more popular?
- Does there exist $f:(0,\infty)\to(0,\infty)$ such that $f'=f^{-1}$?
- Question about Feller's book on the Central Limit Theorem

- Prove that $h'(t)=\int_{a}^{b}\frac{\partial\phi}{\partial t}ds$.
- Solving recurrences of the form $T(n) = aT(n/a) + \Theta(n \log_2 a)$
- How to show that the set of all Lipschitz functions on a compact set X is dense in C(X)?
- Theorem 6.10 in Baby Rudin: If $f$ is bounded on $$ with only finitely many points of discontinuity at which $\alpha$ is continuous, then
- Divisor function asymptotics
- How hard is the proof of $\pi$ or $e$ being transcendental?
- Differential Equations with Deviating Argument
- What is the Definition of a Measurable Set
- This integral is defined ? $\displaystyle\int_0^0\frac 1x\:dx$
- Prove $\csc(x)=\sum_{k=-\infty}^{\infty}\frac{(-1)^k}{x+k\pi}$

- Low-rank Approximation with SVD on a Kernel Matrix
- Theorem 20 Hoffman Kunze Linear Algebra book Section 3.6
- Why are very large prime numbers important in cryptography?
- An interesting geometry problem about incenter and ellipses.
- Complex power of complex number
- ordered triplets of integer $(x,y,z)$ in $z!=x!+y!$
- Determinant of matrix exponential?
- invertible if and only if bijective
- How many random samples needed to pick all elements of set?
- When is the Lagrangian a constant of motion?
- Implementation of a simulation of an incompressible Newtonian fluid with uniform density
- another form of the L'Hospital's rule
- Triangular matrices proof
- Inequality involving inradius, exradii, sides, area, semiperimeter
- Property of critical point when the Hessian is degenerate