Confused Definition and 1000 Threads

How do I determine if I subtract or add the coefficient to the fraction? ex. 1-(-48/18)*Sh=384 vs 1+(-48/18)*Sh=384? Also, It would be the Sh+Sm=312 where I get the coefficient "from" right, specifically the second "Sh" term where as the sm term is eliminated with -sm. Thanks! (The...

Homework Statement the answer to this question [limit x->0- |x|] given to me by my instructor was -1. (by 0- i mean to say the left handed limit). i have been thinking for the last 15 minutes but could not understand it. i think the answer should be 0 because as we get closer to zero from...

I have read that a function f: A -> B can be defined as an ordered triple of sets (A,B,X), where X is the set of all ordered pairs X = \{(a,f(a)) \in A \times B\}. But ordered tuples are really functions from \{1, ..., n\} to (whatever set under consideration), right? So isn't this a circular...

I'm in my second year in University studying mathematics. I really like math, and people are telling me to go into engineering instead due to the better career opportunities. I have considered engineering before but I'm not sure if I will like it because it's more hands-on and I don't think I'm...

Homework Statement A baseball player leads off the game and hits a long home run. The ball leaves the bat at an angle of 30.0o from the horizontal with a velocity of 40.0 m/s. How far will it travel in the air? [141 m] Homework Equations Equations of motion The Attempt at a Solution...

I'm slightly confused as to how we can use the picture of a 2D surface embedded in 3D space as an analogue to understand (maybe not picture!) 4D spacetime. My initial thinking was that trying to imagine a 4D spacetime isn't really possible, it's just a mathematical concept which one should not...

Prove; limit as x->1 (x^3-5x+6) = 2, epsilon=0.2 I got |x^3-5x+6-2|<0.2 Then I don't know where to go from there. Should I add 2 to 0.2 first or subtract 2 from 6 to get x^3-5x+4 < 0.2 ? I'm on mobile can't use latex. Thanks

A second is measured thus: "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium atom." What if the cesium atom itself is moving close to the speed of light? Would that not change the time...

Hi Guys, I'm just a bit confused, or at least I think I am, with the physics relating to panpipes. From my current understanding, panpipes work like this; Air jet is created that enters the pipe, this pressure then forces the undisturbed column of air inside the pipe to oscillate at its...

Hey all, this may sound dumb, but this question has been bothering me for a while now. So we know that moving objects (or people!) measure time moving slowly compared to objects in rest (to them). We also know that distances appear to shrink. Now, first this question: if we send a person...

Bob gets in his car and drives at an average speed of 25 miles per hours (mph) for 4.0 hours due north. He then turns, and drives 75 miles directly east. At that point, Bob turns again and drives 50 miles due south and stops. Draw a diagram with a coordinate system and finds Bob's total...

Hello, thanks for reading! I am slightly confused. According to the definition of the directional derivative, calculated at the point x in the direction y, f'(x;y) = lim\frac{f(\vec{x} + h\vec{y})-f(\vec{x})}{h}, h-->0 According to this definition, the directional derivative seems to not...

This is from a electric field problem I'm trying to solve. This part I'm asking is geometry. I'm trying to find the distance from a corner of a equilateral triangle to its center. Also, I have to find the distance from the midpoint of a baseline to the center of the triangle. Let's assume...

Frederick comes up with the following scheme to measure a building's height. A timing mechanism is set up which measures the time taken by an object dropped from the top of the building to fall the last 2.0 m before it hits the ground. The object is found to take 0.125 s to move the last 2.0 m...

I have been consulting different sources of analysis notes. My confusion comes from these two definitions \begin{defn} Let S be a non-empty subset of $\mathbb{R}$. \begin{enumerate} \item $S$ is Bounded above $ \Longleftrightarrow\exists\,M > 0$ s.t. $\forall\, x\in S$, $x\leq M$...

In my book of formulas I have a formula for energy in different states, particle in box. E_n = \frac{n^2 \pi^2 \hbar^2}{2ma^2} So I should get Joule or something here right. A quick look at the formula. E_n = \frac{n^2 \pi^2 \hbar^2 [Js]}{2m[kg]a^2 [m^2]} \frac{ [Js]^2}{[kg]* [m^2]}...

I'm a computer engineering major and I would like to work designing hardware and systems. I believe I'm a great inventor and think in a very abstract fashion. My grades on non math classes stink, but my math and physics grades are well above the "A" curve. Scoring from 85-100 on exams. points of...

if using hbar=c=1 and ev for mass/energy what are appropriate distance units? Wikipedia talks about inverse energy without really explaining them

I added an attachment and highlited my question... basically I am confused how they got there.

hello, I'm examinating the theorem of power series, specially taylor series I know a function f(x) can be written as a series of polynomials. but using the taylor series it says that the convergence of that function is about a point a by using the Maclaurinseries a = 0 , so examinating...

Hello, After a theorem stating that the product, sum, etc of two elements of a field extension that are algebraic over the original field are also algebraic, my course states the following result (translated into english): but later in my course it defines "the algebraic closure of F" as...

confused undergrad! hey guys, i'm about to start my junior year (double majoring in physics and computer science) , couple of questions, would i be eligible to apply to grad school for applied math (i'm interested in development of quantum algorithms) , also what kind of a jobs would i be able...

My background in linear algebra is pretty basic: high school math and a first year course about matrix math. Now I'm reading a book about finite-dimensional vector spaces and there are a few concepts that are just absolutely bewildering to me: dual spaces, dual bases, reflexivity and...

Confused! -- Max frequency versus fundamental frequency Hello I understand the following question is very silly, however I am not sure about the answer. Let's consider we are saying there is a signal with a frequency of 4 Hz (for example). In such a statement, does it mean the maximum...

Hello! There is something I can't understand... \psi(0)= \frac {1}{\sqrt 5}|1>+ \frac {2i}{\sqrt 5}|2> I need to find <H> for \rightarrow \psi(t) For E_n= \hbar \omega (n + \frac {1}{2}) , \hat {H} =(a^\dagger a+1/2) These make me understand that this problem is one dimensional. (+1/2 in...

Confused in graphs? Homework Statement My teacher gave a question in which he have to find the number of solutions:- 10sin(x)=x I solved it using the graphs and i got the number of solutions to be 4. But when i came back home and tried to do it on Microsoft Mathematics, i found the results...

Hi I have a question about POVMs im confused as to how they correspond to actual measurements we do in a lab, and how non-orthogonal measurements fit into this context. For example we have some POVM with elements E_i. I read in Nielsen and Chuang that we do a measurement and get outcome m...

Can someone explain what the difference is between the expectation value of an observable in a pure vs a mixed state. The equations are identical. For example with spin up and down |A|^2<S_u|O|S_u> + |B|^2<S_d|O|S_d>

Please use zoom function for better view. I'd highly appreciate it if you could also add a diagram on your explanation. Thanks!

Future of a particle in a box -- I'm fundamentally confused Homework Statement A particle is somewhere in the right half of a one-dimensional infinite potential well with sides at x=-a/2 and x=a/2. The particle's wave function is constant over x, i.e. \psi(x) = \sqrt{2/a} for 0<x<a/2...

So here's the deal. Nothing in Science has EVER been confusing, made no sense, seemed totally unacceptable, or anything like that. And I don't know why. All this "confusing" Quantum Physics made perfect sense to me. Time dilation and relativity? Not confused. Double slit experiment? Perfectly...

Hello, In the chapter on thermal noise it says that the spectral distribution per Ohm of resistance is a certain shape (constant till a certain f and then ~ 1/f²). What is this expression? Is it physically the power dissipitating in the resistor, at least a certain part of it...

I am confused over something about voltage and current. A transformer increases/decreases the voltage in a circuit and does the opposite to the current. The current times the voltage has the same value before and after. This however, seems to go against the well known equation V = IR (the...

I am a bit confused at "orthonormal tetrad" in General Relativity... I think orthonormal tetrad should be a set of vectors like [FONT="Georgia"]e0= (1,0,0,0) e1= (0,1,0,0) e2= (0,0,1,0) e3= (0,0,0,1) However, in my book, it is written as [FONT="Georgia"]e0= (-1,0,0,0) e1=...

As the title says, I am confused - very confused. I know that the 2nd law of thermo means that the universe is increasingly disordered on a universal scale, even though there has been an apparent increase in order since the "Big Bang." Does that mean entropy isn't exactly synonymous with a...

Seriously confused, please help! Hi there. These are just a few questions I just can’t get my head around. I don’t understand HOW: a) HOW an air bag reduces injury exactly – Question says ‘Explain how an air bag reduces the risk of head injury in an accident’ – I know that the air bag inflates...

i am still confused how to prove that a set is a basis other than proving it linearly independent and system of generator that have to do with matrices? please help

Homework Statement An Earth station receives data transmitted back in time from a future intergalactic expedition. The table summarizes the data for the moons of a planet that will be discovered in a distant galaxy. Moon 1: only has orbital radius = 5E7 meters Just only this...

Homework Statement Prove that lim a_n = L given that (a_n) is a sequence defined such that every subsequence has a convergent that converges to L\in R Homework Equations Bolzano-weierstrass and the works The Attempt at a Solution A subsequence of a subsequence is just a...

hi. I have asked for help on this again but i got even more confused. The question says solve: dx/dt - 2t(2x-1) = 0 when t=0 when x=0. I did: 0.5 ln(2x-1) = 2t^2 / 2 + K then i have 2x-1 = 0.5(e^t^2) + K putting x=0 and t=0 i get: K=0 thus i have 2x-1 = e^(2t^2) thus...

Is it Osama or Usama? The FBI Most Wanted List has Usama but CNN says Osama. Personally, I have always used Osama. Opinions?

Hello, I'm reading Griffiths' Introduction to Electrodynamics and I got quite confused in 9.4.1 page 392 (but the question is general, for anyone who does not have that book): It's about EM-waves in conductors. I will quote a paragraph: What is the definition of bound (or free)...

If an object is moving forwards on a rough plane, we assume that there is a force opposing its motion, namely friction or resistance. This friction includes the friction because of the contact between the moving object and the ground. From Newton's third law, we can conclude that because the...

Homework Statement Prove\; that\;if\;\sum_{n=1}^{\infty} a_n \;converges,\;then \lim_{n\to\infty}a_n = 0 Book solution s_n= a_1 + a_2 +...+a_n s_{n-1}= a_1 + a_2 +...+a_{n-1} a_n=s_n-s_{n-1} Then they did a few limits, and proved that the difference is 0. BUt that is not my...

I'm writing a flight sim for use in Cinema 4D, an animation package that has a built-in physics engine. It's not supposed to be totally realistic, and I've got most things working fairly well. But one thing I don't understand is how to calculate lift correctly when the relative wind isn't coming...

One common explanation of the concept of D.F. is this: Suppose you have n numbers (a, b, c,...) that make up a sample of a population. You want to estimate the variance of the population with the sample variance. But the sample mean m is being calculated from these numbers, so when...

Homework Statement dU = dQ + dW so dU = Cv dT... but only if dW is zero right? as dQ = CvdT so then the central equation is TdS = dU + PdV which is then TdS = CvdT + PdV according to my notes. surely PdV should be zero no?

I've just finished some past exam papers and when marking them using the mark scheme something confused me a little One question said when a fire engine moves away from an observer, the pitch of the siren decreased, why and I chose the wavelength of the sound wave decreases The mark scheme...

I'm really confused! The Dirac equation describes spin -1/2 particles - i.e. particles of definite spin. And yet the spin operator does not commute with the Dirac Hamiltonian! The reason I'm confused is because I thought if you were going to describe particles of a given kind - that is...

total pressure , I'm confused ! hello :) i'm new here ... i'm confused in poits regards pressure now please correct me if I'm wrong... 1-static pressure is equal to the total pressure if the gas is static (V=0) 2- total pressure is always equal or bigger than the static pressure 3-as...