Approach Definition and 565 Threads

My logic is that if I am to lose weight the mass of material entering my body must be less than the mass of material exiting my body. Never mind Calories. My procedure is this, before each meal I weigh myself. If I weigh less than my immediate goal then I eat, if not then I don't. After each...

Homework Statement Question: Blue light of wavelength 485.6nm from a star is incident normally on a diffraction grating. The light is diffracted into a number of beams, as shown in Fig 5.4.(attached) The angular separation of the two second-order beams is 45.72 degrees. Calculate the...

1. What is the probability of tossing at least three 'heads' if a fair coin is tossed four times? 2. Drawing a tree Hey guys, I was just wondering...is there a mathematical approach for me solving this question without drawing an event tree? Reason I ask is so that it saves time...

Homework Statement A transverse wave on a cord is given by D(x, t) = 0.19sin(2.9x - 35t), where D and x are in m and t is in s. 1) At t = 8.6*10^-2 s, what is the displacement of the point on the cord where x = 0.62 m? 2) At t = 8.6*10^-2 s, what is the velocity of the point on the cord...

Richard Feynman's "sum-over-paths" approach to quantum mechanics? I am in terrible need of some insight or clarification. I have two questions. In the double-slit experiment, when a particle is ejected whether it be photons or electrons (I will use electrons in this question), when streams...

I was searching for the proof of \frac{d}{dx} e^x = e^x. and I found one in yahoo knowledge saying that \frac{d}{dx} e^x = \lim_{Δx\to 0} \frac {e^x(e^{Δx}-1)} {Δx} = \lim_{Δx\to 0} \frac {e^x [\lim_{n\to\infty} (1+ \frac{1}{n})^{n(Δx)}-1]} {Δx} Let h= \frac {1}{n} , So that n = \frac...

Hello i want to move an object with core magnetic filed.could you tell me how can i do that?and what is formula?

Homework Statement The problem is given as a piece-wise function f(t)={1, 0≤t<4; 0, 4≤t<5; 1, t≥5}. I am asked to write the function in terms of unit step functions and then find the Laplace Transform of the function. I can do the Laplace if I could ever get the unit step function...

Homework Statement This is an exercise from 'How to Prove it - A Structured Approach' (Exercise 7a, page 54) . So far a a really great book. Homework Equations The DeMorgan, Absorption, Idempotent, Double Negation, Commutative, Associative, Distributive, Tautology, Contradiction...

Who can explain the following questions about transfer matrix? formula (31) in New Journal of Physics, Vol.12 123020. [http://iopscience.iop.org/1367-2630/12/12/123020/pdf/1367-2630_12_12_123020.pdf] is different from the result of another paper in Journal of Physics:Condensed matter...

Difference between approach for show that ... and prove that ... Whats the difference between how you solve a problem that involves showing or proving something? For example what would be the difference between the solution to: "Show that \sin\theta(2cos\theta+sin\theta) can be written as...

I have a question regarding an oscillator design from a controls perspective. An ideal harmonic oscillator has just 2 poles, both on the imaginary axis, and their location along the axis determines the frequency of oscillation as well as the amplitude. Now, please correct me if this is...

Hello physics forum. In last couple of weeks i have been working more difficult problems from Algebra and things are going a bit more difficult where solution is not apparent right away. So i need to spend some time doing one problem until i find a solution. That can be from half an hour to...

Given that certain nullspace is spanned by a vector v, what would be the procedure to project out the v component from certain vector u? Perhaps with the Gram-Schmidt process of orthonormalization by updating v = v - proj(u, v) where proj(u, v) = (<u, v>/<u, u>)u, and <u, v> denotes the...

$\displaystyle \int_{0}^{\infty} e^{-ix^{2}} \ dx = \lim_{R \to \infty} \int_{0}^{R} e^{-ix^{2}} \ dx $ I think I'm perfectly justified in treating $i$ like a constant since we're integrating with respect to a real variable.$ \displaystyle = \frac{1}{\sqrt{i}} \ \lim_{R \to \infty}...

Homework Statement What is the probability that given a group of 5 people, at least 2 will share the same birthday? Homework Equations I know that 1-P(0 matches) = answer, but there is a reason I am going about this the head on approach. I am trying to develop my combinatoric skills.The...

Is it really impossible that gravity can be modeled non-geometrically? I read the following in Weinberg paper Gravity: "An alternative way to conceive of gravity would of course be to follow the lead of other theories, and regard the gravitational field as simply a distribution of...

Hello all! :smile: In my quest to re-teach myself the basics of mathematics in a more rigorous fashion, I have found out that inequalities and absolute values are a weak point if mine. So I am working to address that. I am getting much better at it (with help from PF), but I have recently...

Hi there, I was hammering out the coefficients for the Taylor Series expansion of f(x) = \frac{1}{\sqrt{1-x^2}}, which proved to be quite unsatisfying, so decide to have a look around online for alt. approaches. What I found (in addition to the method that uses the binomial theorem) was...

Ok here's the problem: Using wolfram the first 100 results are these heres a plot of a couple points As you can see it doesn't seem to be approaching exactly zero, even though its very similar to 1/x (exactly the same if you replace Pn with just n) Is there any way to prove whether this...

Homework Statement Given this one period graph of a function with period 2pi, find a Fourier expansion.Homework Equations The Attempt at a Solution So I was wondering if i can split up the integrals into two parts to find the coefficients. It is an even function so ak = 0. for bk can I...

Homework Statement A particle, unknown mass, has velocity v0 and impact parameter b. It goes towards a planet, mass M, from very far away. Find from scratch (? I'm not sure why it says from scratch), the distance of closest approach. Homework Equations I believe this equation is...

How would I analize a bolt in tension and shear. Imagine an "L" bracket bolted in the configuration below "||" represents a bolt. There is a force "<--" at the top of the bracket. <--| ...| ...|_____||_ The bolt will see tension and shear. There will be tension in the y direction (Sigma...

Homework Statement Homework Equations Fourier transform, Gaussian filter The Attempt at a Solution First of all, someone in the class did it correctly and here's what they said: Second of all, let me make sure I have a correct understanding of this. We...

Greetings all, In going through an operator approach to deriving the rules of angular momentum I find myself asking a curious question. Is it possible to fully derive the Angular momentum algebra relying on only a minimal set of classical relations. That is to say, if we take the only...

The prime numbers are the multiplicative building blocks of the integers. Even so, their distribution escapes all methods of rationalization. As with building a pyramid, the primes are most densely distributed near zero, the point of origin, and as we move towards larger numbers the primes are...

I think about this every time I look up at the stars and think about the fact that what we're seeing is the sky as it existed X years ago, depending on how far away the star is. So let's say we're traveling toward a planet at near light speed, do you watch it age at a rate relative to the time...

I'm currently enrolled in precalculus and I'm finding that almost everything we've learned so far is just Algebra 2 review. I've been looking for a book where I can self study Calculus and move ahead, and I stumbled upon Calculus: an intuitive and physical approach by Morris Kline. I am...

I've been given this problem http://i.imgur.com/7XtYt.png and I had no idea of how to come up with an answer since it is a circular path. The only thing that occurred to me is find the initial height using the chord length formula for a circle and then treat that chord as the hypotenuse of a...

Homework Statement Find the average value of : f(x) = 4sinx + 4cosx on the interval [0, 16pi/6] Average value: ? Homework Equations Integrals The Attempt at a Solution 1/ [(16pi/6) -0] ∫ from 0 to 16pi/6 4sinx + 4cosx dx [3/8pi] ∫ from 0 to 16pi/6 4sinx + 4cosx dx <------simplify...

Mesh Current: Cannot see my mistake in my approach? Homework Statement Find currents I1, I2, and I3 using Mesh Current Analysis in this circuit: Homework Equations KVL The Attempt at a Solution Initial equations: Mesh 1: -120 + 20k(I1) + 40k(I1 - I2) = 0 Mesh 2: 40k(I2 -...

Homework Statement Assume the spring force of a bowstring acting on an arrow does not follow Hooke’s Law because the bow’s material becomes more rigid as it is drawn back. The string’s force as a function of the drawback distance in meters is: F(x) = -k1x -k2x|x| where positive x is along...

Hi! How is "Microelectronics : An Integrated Approach" by Roger T. Howe and Charles G. Sodini ? A friend suggested me this book. No reviews available for this book in Amazon. Experts and readers please comment. :smile:

This is the question: A massless spring with a spring constant of 0.50 N/m, has a mass of 0.7 kg on its end. The maximum speed of the end is 2.5 m/s. What is the angular frequency of the system? I don't know how to approach this problem at all. I just know that omega/2pi is the...

Hello everyone! After having being asked to help prepare a simulation(using computer programming), for the general(numerical) solution to Kepler's orbits(strictly speaking, for any central force, and for simplification, no other is acting here), I ran into a bit of a rut trying to resolve some...

I've been searching for a good book on Calculus that is great for self-study, and at the same time, walks the reader through the WHY behind the math. I am farely upset at how today's educational institutions teach math as plug-n-chug subject without walking the students through the underlying...

I was talking with my friend and the best answer i could come up with is "It does." But, i could not explain why. Could you guys help me out? Thanks DM

Determining what value "y" will approach eventually I'm having a bit of trouble with an equilibrium problem. The autonomous equation given is: y' = (2y+8)(y-3)(y-8)^3 The first task is to find and classify the stability of each equation, which I've done. Points: y=-4, y=3, y=8...

Hi forumers! I have a concept for a DSLR boom crane and I want to operate it using stepper motors via belts/gears or pulleys. It will be mounted on a driven turntable bearing on a tripod. The boom acts like a see-saw when mounted on the turntable. The load distance from the apex of the...

Hi, I am used to do things independently in my life and rarely takes the advice of others. The one important problem I often face is, whenever I try a method i always stick to it even if it doesn't work. I try to fight with the same approach to find solution to the problem in hand. Though I am...

So I've decided that I'm taking Quantum Mechanics this semester but I'm not sure what approach I should be taking towards learning it. Our class is using the standard Griffiths text but after reading the first chapter and a half, although I like his conversational style and think that it's an...

Hello all :smile: I have started the problem set for Chapter one (basic properties of numbers) in Spivak's Calculus (self study). I think I am doing these right, but I have some questions. As a solid example, problem 1-(iv) says to prove the following: x^3 - y^3 =...

Good day People, I require some assist in designing steering system for a vehicle I'm designing I'm trying to upload an idea of what I'm referring too, but Site only allow 300kb and the file is 573kb Any steering ideas out there, that is different from Go kart, Cars, vans etc. In...

Heres the question: http://img194.imageshack.us/img194/9042/vanthoff.png and here's the Van't Hoff equation (the form I like to use): [PLAIN][PLAIN]http://img703.imageshack.us/img703/1577/vtequation.png I'm a bit confused about what's going on here. I see the formula includes ∆Ho, meaning...

Is there any Advanced concepts , theories out there; Instead of the combustion. We're not limited ; direct conversion of electricity to thrust is here, so if you have any ideas leave it here, *Electricity-conversion- microwave- to thrust (radiation pressure difference) *Electricity-conversion-...

Is there an elegant and simple proof of the Chain Rule? Every proof I've found is complex and mind-boggling

I want to write a research paper on general relativity or mathematical physics. I am a college freshman (will become sophomore after this summer) belonging to an engineering major. In this summer break, I have managed to learn about tensors. Currently, I am following the Respected Professor...

I'm doing a literature review on dispersion relations, and I've been told that if i can derive the phonon dispersion relation, it would help my review. So i was wondering if anybody could help me with the derivation either through Quantum-mechanical approach or Semi-classical treatment of...

I'm a novice in Loop Quantum Gravity, so please bear with me if this is a trivial question. As far as I know, LQG is usually formulated non-perturbatively, but is there also a perturbative approach in the sense that we use a series expansion in order to calculate vacuum expectation values? Are...

ok so here is what i was thinking when a spaceship enters the atmosphere the reason for the high impact velocity is that the air is spinning at 66000mh AND that to keep an orbit you need certain speed with is different from the Earth's rotation... now if you slow down/speed up to match...