Sharp Definition and 57 Threads

Hi I am trying to remember the name of the situation in logistic regression when all data points beyond a fixed one are all successes or all fails. So we have data points## ( a_{i1}, a_{i2},.., a_{in} , 0/1) ##, with data points ##a_{ij}##ordered; last input a Boolean and a fixed value for j...

Pardon the very naive question, but why does the atmosphere in these gas giants seem to have, from a distance, a very clear, sharp and distinctive boundary? When one looks at Earth's atmosphere from space, it seems to have a fuzzy bluish boundary, gracefully vanishing into the black. I read...

I was reviewing an old topic for me that's x-ray diffraction, and one doubt I always had in my mind arised again. When introducing the Bragg's law, the typical explanation is that the x-ray waves reflecting in two adjacent planes interfere with each other, leading to a fully constructive...

First of all, Let me present some of the things I found from research. (considering convex lens) Interpretation 1 => Focal length is the distance from the center of the lens to the point where all rays converge. Interpretation2 => Focal length is the distance from the point of convergence to...

This is an inquiry about some of the details of the bending of the trajectory if a photon by curved space-time (S-T) from the perspective of general relativity (GR). The environment in this scenario contains a black hole at its center, a photon passing by the black hole a km above the event...

Hi everyone, Apologies for what may be a relatively obvious question for you but I'm struggling to understand a concept that was discussed in my introductory Physics class. I would really appreciate any help you could offer. During an explanation of sound, we were told today that a sharp sound...

I am reading R. Y. Sharp's book: "Steps in Commutative Algebra" Cambridge University Press (Second Edition) ... ... I am focused on Chapter 1: Commutative Rings and Subrings ... ... I need some help with Exercise 1.29 ... Exercise 1.29 reads as follows:I am somewhat unsure about how to go...

Homework Statement I am reading R. Y. Sharp's book: "Steps in Commutative Algebra" Cambridge University Press (Second Edition) ... ... I am focused on Chapter 1: Commutative Rings and Subrings ... ... I need some help with Exercise 1.29 ... Exercise 1.29 reads as follows: Homework...

Homework Statement ∫ e1000((sinx)/x) dx [0 to 1000 : bound of integration]. Solve this integral of a sharply peaked function without a calculator. Homework Equations I'm doing this in relation to statistical thermodynamics - I think I need to use Sterling's Approximation or a gamma function...

I wish to display symbols like < and > as in < z_n > but more like the symbols in the following text ... Hope someone can help ... Peter

A few dozen years ago the endings of lightning rods were sharp. I read somewhere that it served one purpose - it enabled the flow of charge between the ground and the cloud, thus reducing the voltage and lessening the probability of another lightning. What I don't understand is why this sharp...

Hello all, I was wondering, for modifying the sharp edges of a shaft, which one of the cases attached is better? Why? My guess would be the one with the radius since there are more materials remaining than the other but there should be a reason for the other case since that is also frequently...

Homework Statement Hi everybody! Being given three identical thin lenses with the same focal length, I have to determine ##a## (distance object-screen), ##d_a## (distance lens 1-lens2) and ##d_b## (distance lens 2-lens 3) so that a sharp image of the object appears on the screen regardless of...

https://en.wikipedia.org/wiki/Zero_sharp Here: I don't understand how large cardinals are related to this. 0# is countable, just set of integers, why do we need "extra constant symbols"? Obviously, set of Goedel numbers of all true formula "exists" (in human sense) anyway (no matter if...

On the Schrodinger cat, can I simply say, outside the box,the state is in superposition,but inside the box, the state is not. Besides, the experiment is so simple to do, how come no body ever did it ?. Just put an animal you hate or even an inset, and observe the expected (50% -50%) result...

intuitively it makes sense but what is the scientific explanation

Using a high-power LED light (the surface mount kind, about 4x4mm with 120 degree viewing angle) I'd like to project shadows of a fine metal mesh onto a wall. I have tried various lens arrangements and found that placing a pinhole in front of the LED makes the sharpest shadows. This makes...

OK, recently I've been having weird sharp sensations in my chest, it started in the left side but now it happens in the right too, the doctor said it was because of my weight training and that i had to stop, so i stopped but its been over a month now and it's still carrying on, also sometimes i...

Hey all, I'm reading through an anecdotal work about the philosophical foundations of quantum field theory and the authors keep referring to states having the ability to be "sharp." As in it's possible for P to be sharp if the system is mixed, where P is some property of the system. Thanks! IR

Hi... I want to know why charge density is higher at sharp points in a conductor? I have gone through the analogy of two spheres connected by a wire... But is there any other explanation which is not specific to spheres...?

Homework Statement For a particle of mass m in a one-dimensional infinite square well 0 < x < a, the normalised energy eigenfunctions ψn and eigenvalues En (integer n = 1, 2, 3, ...) are $$ \psi_n(x) =\sqrt{\frac{2}{a}} sin \left( \frac{n \pi x}{a} \right) \;$$ inside the well otherwise...

I have an old Windows Vista PC that has started acting up. Normally it is in the sleep mode. Lately when I push the start button the fans start running for 2-3 seconds and then it shuts down. This can happen many times in a row but if I lift one side of the computer case a bit (which lies flat...

I was thinking about the principle of energy density and how sharp knives cut so easily because their surface areas are tiny and thus any force applied to them is imparted on this tiny area. So my question arises, does anyone know just how sharp the sharpest knife/ sword is? Let's no discuss...

Ive had this problem with the calculator since I bought it. It might be that the calculator does not have enough implemented functions to pull it off or I am missing something. It happens when I am solving for imaginery roots. Example: y^2 + y^1+y = 0. I go to mode, and select 6(equation)...

In R. Y. Sharp "Steps in Commutative Algebra", Section 2.23 on sums of ideals reads as follows: ------------------------------------------------------------------------------ 2.23 SUMS OF IDEALS. Let ( {I_{\lambda})}_{\lambda \in \Lambda} be a family of ideals of the commutative ring R . We...

I am reading R Y Sharp: Steps in Commutative Algebra. In Chapter 3 (Prime Ideals and Maximal Ideals) on page 44 we find Exercise 3.24 which reads as follows: ----------------------------------------------------------------------------- Show that the residue class ring S of the ring of...

I am reading R.Y. Sharp: Steps in Commutative Algebra. Lemma 1.13 on page 7 (see attachment) reads as follows: -------------------------------------------------------------------------------------- 1.13 LEMMA. let R be a commutative ring, and let X be an indeterminate; let T be a commutative...

Hello everyone, Could someone explain or direct me to some detailed explanations as to why is the electric field at a conductor greatest where the curvature is sharpest? I just can't seem to grasp this concept. I understand sharp edges do have this property so is this that there is more...

I am reading R. Y. Sharp: Steps in Commutative Algebra, Chapter 5 - Commutative Noetherian Rings Exercise 8.5 on page 147 reads as follows: -------------------------------------------------------------------------------------------------- 8,5 Exercise. Show that the subring \mathbb{Z} [...

Homework Statement Consider the function in polar coordinates ψ(r,θ,\phi) = R(r)sinθe^{i\phi} Show by direct calculation that ψ returns sharp values of the magnitude and z-component of the orbital angular momentum for any radial function R(r). What are these sharp values? The Attempt at a...

Hi everyone.. I was doing some experiments on diffraction and interference. For the single slit I used a shaving razor blade and cut it into half along its length. Then I placed the two halves together forming a slit such that the two sharp edges almost touched each other, similar to the one in...

Why is the electric field strong in sharp points?? There is a question in my book regarding the intensity of the electric field near a sharp surface in a conductor. There is a hint which says that it will be helpful to examine the field lines near those sharp surfaces. This is from my...

Homework Statement Make a rough estimate of the ionisation potential of potassium (19) given the following infomation relating to its optical spectrum: wavelength of the first line of the Sharp Series: 1248nm wavelength of the first line of the Principal Series: 767nm wavelength of the...

Homework Statement Two charged conducting spheres of radii a and b are connected to each other by a wire. What is the ratio of electric fields at the surfaces of the two spheres? Use the result obtained to explain why charge density on the sharp and pointed ends of a conductor is higher than on...

In the EL-520X, where is the function to find the greatest common factor or the lowest common multiple? In an older version of Sharp, I could find it, but for this one I can't. Thanks...

"Playing" with math keeps me sharp! I'm pretty new to math, just taking Calc II and a proof class. But every once in a while, while doing homework, I get obsessed with looking for patterns in math and expressing them. They are usually pointless, and come out to be kind of "duh" in the end...

I read somewhere that a single particle traveling freely (not in a box, no PE function, etc.) cannot have a sharp energy. Is this correct? If so, why? As always, thanks in advance.

Flow rate measurement: Venturi vs Sharp edged circular orifice. Help! :) Homework Statement Hello guys, I am having trouble answering these questions. I know the the discharge coefficient for a venturi is always higher than that of the sharp edge orifice. Can you guys help me out with the...

I got a problem described by a displacement time graph. It has sharp turnings at 2 points ( and sucessives) and the question is to convert the graph to velocity time graph. Since sharp pionts are not differentiable how it can be drawn ?

So if I leave my steel strung guitar overnight in my cold basement, it goes out of tune on the sharp side. Now if I want to manually tune my guitar sharp, I have to tighten the strings = i.e. put energy into the system and do work. So where does the energy come from to do this in a cold...

How will the angle of the sharp edged orifice affect the flow pattern. Most of the angle is encourage to keep at 30 or 45 degree. For a study vortex generation by pushing the water through a sharp edged orifice, what is the optimum angle I should adopt or what consideration should be made...

What are the theoretical and practical reasons that no particle can have an absolute sharp position? Is it because the position operator has no eigenvectors, i.e. position eigenstates are never descriptions of actual physical states (because they are Gaussian vectors with a certain width)...

https://www.youtube.com/watch?v=F_PT5yu976Y http://www.lcdtvbuyingguide.com/hdtv/sharp-quadcolor.html A Gimmick, overreaching, or the new standard?

Hi with respect to the bremsstralung and the Xray emission, i have a graph of the xray emmision and at the end of the bremsstrahlung, at roughly 35 KeV,there is a sharp cut off. Is the reason for this because that 35KeV is the maximum energy of the incident electrons, and hence no photon...

Hello, I believe we have seen that when a car is traveling in high speed and wants to make a sharp turn, the outer wheels actually sort of like lift of the ground right? What is the cause of this? I was thinking that it might have something to do with moments about the inner wheels? Its has...

A candle is placed 1.8 m from a screen. whereshould a lens of focus length 21 cm (0.21 m) be placed between the screen and the candle to prduce a sharp image screen? The only formula i could think of was 1/f=1/do+1/di I've now spent 3 hours on this (test tomorrow) and still don't know...

Carlo Rovelli and Lee Smolin have recently taken diametrically opposed positions on whether time is a basic part of reality or merely an emergent feature----like for example temperature, or the surface of a liquid. The surface of a liquid is well-defined at our macro scale, but if you look...

Homework Statement Why does a sharp knife cut better than a dull knife? Explain using Newton's Laws. The Attempt at a Solution 1st Law: Since the sharper knife has less surface area, it keeps more better than the dull knife. The friction is less. 2nd Law: Less surface area on knife...

1. A lamp and a screen are 1m apart and a +4.5 D thin lens is mounted between them. Where must the lens be placed in order to produce a sharp image on the screen, and what will be the magnification? 2. Gauss Law: L' = L + F 3. I attempted this question by using the Gauss Law but I...

I am an artist. I am trying to cast a large sharp (in focus) shadow through a piece of lace onto a wall. It either turns out large and blurry if it is far from the wall, or sharp and small if it is closer to the wall. I have tried the following experiments: 1. Increased the focus and...