Formulas Definition and 545 Threads

Hi folks, I am in the energy industry, and we do linear/multilinear regressions stats. One of the concepts being introduced to supplement standard way of doing regressions is make use of: (1) Coefficient of Variation Root Mean Squared Error (2) Net Mean Bias or Abs (Mean bias)...

I am going to make a R.C. airplane and need help understanding the physics behind it. I have found these formulas for lift and drag. Lift=Cl*(r*V^2)/2*A Cl=2*pi*AoA Drag=Cd*(r*V^2)/2*A Cd=Cd0+Cl^2/(pi*A*R*e) Now I have two questions. First, are these the correct formulas for finding...

Homework Statement 1. write Newton's law in terms of s'' theta and g for a pendulum 2. define s'' in terms of theta'' Homework Equations The Attempt at a Solution 1. G = -mgsin theta and G = m s'' but i can't get all three of the required variables into one formula...

Homework Statement For the following series, write formulas for the sequences an, Sn and Rn, and find the limits of the sequences as n-->infinity Homework Equations N/AThe Attempt at a Solution an is easy, = the limit of which does not exist. This is where I get stuck, I know Sn= But I don't...

Homework Statement Of the following, which correctly shows an ion pair and the ionic compound the two ions form? Homework Equations a. Fe3+, O3+ = Fe2O3 b. Cr3+, I- = CrI c. Cu2+, O2- = Cu2O2 d. Sn4+, N3- = Sn4N3 The Attempt at a Solution a. Fe3+, O3+ = Fe2O3...

Homework Statement Find simple formulas for 1+ cos(θ) + cos(2θ) + cos(3θ) + ... + cos(nθ) and sin(θ) + sin(2θ) + sin(3θ) + ... + sin(nθ) The Attempt at a Solution It's not really a homework question, but more for making a problem that I'm trying to solve a little bit more simple...

Hi. I know about the general formula for an ellipse: x^2/a^2 + y^2/b^2 = 1, that can be used to isolate y and calculate x,y points in excel. That's great, so far so good. That will create a ellipse, with horizontal A (x) axis and vertical B (y) axis. But what if one wants to rotate the...

Homework Statement I can make intuitive sense out of cofunction identities but the compound angle results completely blows my mind. Is there a way to make sense of them without having to think about the proof everytime? Or should I just memorize them Homework Equations The...

just revising for gcse's and there always seems to be a question with three unknown denominators and you have to rearrange the equation they are usually like 1/a+1/b=1/c make b the subject of the formula can you explain how to do this

I am looking for Physics books which that focuses on how the Physics formulas are derived. I know that some formulas were derived by experiments and how each of the controlled variables relate to each other. That is fine for me too as long as it has the experimental data; although i prefer it to...

2 Questions please hello. i need help to Understand how can i Write Empirical formula for Al or in general how to Write Empirical formula? 2)i also need help to Understand how can i know what Ion i will get from Ba and P ? i think for ba is will be Negative because there more...

Hi to everyone I'm new to this forum and if someone knows about formulas or how to generate the arithmetic and progression geometric and with the software Mathematica 5.0?! Both of these have starting member and step for calculation...Thanks in advance, G.S

Homework Statement Just wanted to find some clarity regarding this subject. In my textbook, it states that Q = nCvdT for constant volume and Q = nCpdT for constant pressure. However, one of the TA's in my classes were telling us how dU = nCpdT for constant pressure and dU = nCvdT for...

z_k=\sqrt[n]{u}=\sqrt[n]{r}e^{i\left(\frac{\phi+2k\pi}{n}\right)}, k=0,1,2,...,n-1 and z_k=\sqrt[n]{u}=\sqrt[n]{re}^\frac{\phi+2k\pi}{n}, k=0,1,2,...,n-1 Which one is incorrect (note that in the first, e is out of the root)?

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What are usual tips in conjecturing formulas for math induction if I am given a certain sum of sequence? Thank you.

Homework Statement When do i use: (delta)Y=Viy+(1/2)ayt2 Compared to... (delta)Y=Viy-(1/2)ayt2 What tells me if I am going to be using (+) or (-)

Homework Statement I'm needing to write a program for thermodynamics, but before I can write the program, I need to find formulas for the heat capacity of a few substances: Al, Fe, BaTiO3, and Polyethylene. Ideally, I'm looking for equations that explain this behavior between 298K and 600K...

Hey. I was not sure if I could post this somewhere else, since this has nothing to do with homework or anything like that. Homework Statement In a Newtonian world: Determine the position of object two, being x, z spatial coordinates and y a time one relative to object 1. Object 1 is (0; y; 0)...

what determines what order the atoms in a formula are written? for example, why is it CO2 and not O2C? It doesn't appear to be ordered by atomic weight, place on the peridoic table or alphabetically so what is it?

I'm relativly new to quantum ohysics and have only read a few books, please can people explain some of the equations and the maths of quantum physics I can understand matrices and diracsc equations but please and somebody explain the maths of probability and other matters thx

Homework Statement I copied these formulas down that my professor had written on the board, but I have no idea how they may apply to velocity or acceleration. Homework Equations v=at+v0 v-v0=a(t-t0) v1=10(1)+0 = 10 m/s I believe that the 10 represents gravity, but don't...

Suppose f(n,p)=integral(n!/(x! (n - x)!dx, for x from -1/2 to p) where n>1, p<n+1/2 Are approximate formulas known for this kind of integral? Empirically, f(n,n+1/2) seems to be close to 2^n More generally, I'm looking for approximate formulas for integrals of n!/(x1!x2!...xn!) over nice...

So how did people like Einstein, and Newton really do it on a day to day basis? How do physicists really do physics? Is it a bunch of scientifically minded mathematicians sitting around doing lots of math until the results they get match experimental ones, or is it more a matter of doing...

Hello, it is mentioned http://en.wikipedia.org/wiki/Atan2#Definition" that using the tangent half-angle formulas it is possible to express the function atan2 as: \mathrm{atan2}(y,x)=2\mathrm{arctan}\frac{y}{\sqrt{x^2+y^2}+x} How can I derive this result?

I have problems solweing this task. In magnetic field with induction 0.25 is a flat coil which has N=75 whrols with a radius of 25cm. Angle between Coil‘s flat and magnetic force lines is 60 degrees. How much torque afects coil in a magnetic field, while there flows 8A of curent? What work...

Using these two formulas derive the third formula: D/l = (D+f)/(l+alpha) D/r = (D+f)/(r+beta) D=(fb)/(alpha+beta) where D is the distance of the point from the line between the viewer's eyes; f is the focal length of the lens in the eye; b is the distance between the two eyes; and...

Homework Statement The current in a 4.70 mH inductor decays over time according to the following function, where t is in seconds. I(t) = (.943A) e-(396 s-1) t) (a) What is the induced emf across the inductor at t= 5.00 ms? (b) How long does it take the emf to drop below 1.25 mV?The Attempt...

So I am trying to derive a formula from one of the standard summation formulas except starting at a different index. So if I have the series.. \sum i = \frac{n(n+1)}{2} Where "i" runs from 1 to n. (I don't know how to put it in the code.) If I want to make the series start from zero, I...

I want to calculate or model the vibration phenomena of tubes (specifically carbon tubes, gun barrels etc): such factors as time before coming to rest, vibration cycle(s), frequency etc that different designs of tubes exhibit when subjected to a force. One question in particular I would like to...

Sorry about that title, I had zero ideas what to put there. :smile: How important is it to learn the backgrounds/how the formulas came about in math and physics? Obviously you need a general understanding, but does one really need to know exactly how these formulas came about/work? Since that...

Does anybody happen to know where to find the perturbation theory formulas for the energies and states up to fourth order? I have to do a calculation up to this order and don't want to have to derive them if I don't have to (I know that Wikipedia has high order energies, but they only have the...

Can anyone give me the formula or equation so I can solve each of these? Homework Statement Question #1 Suppose the Sun is located 7.4 kiloparsecs from the center of the Milky Way galaxy, and that it orbits the galaxy at a velocity of 240 km/sec. Estimate the mass of the galaxy...

can some1 teach me some formula on how to relate power(mW/W) to sound(dBv/dBSPL)?i need some formula about this two topics and relate them because we are having a feasibility study on how to convert sound to electricity and we need some formulas,i know its kind a hard to transform sound to...

Homework Statement I need to determine loading sequences for a box barge - I have lots of information on the actual question, which I can't put up here because I have not attempted this question. I am really after some advice as to where I can find the equations I need. My (merchant navy)...

So I'm taking chemistry again after a five hear hiatus from the topic and I would really appreciate an explanation on a certain formula. magnesium +oxygen forms magnesium oxide Mg+O2=MgO My question is, what happened to the 1 of the oxygen atoms? Shouldn't it be MgO2?

I had to factorise this formula. The answer that I came up with is below: 6ax - 12ay - 18a squared. 6(ax - 2ay - 3a squared) My book says that the correct answer is: 6a(x - 2y - 3a) Would my answer have been marked wrong in an exam? Why is the book's answer preferable to mine...

Homework Statement What are the uncertainty propagation formulas for: Area of a rectangle Density of a sphere Height of an opposite side wall calculated by tan(θ)=o/a ResistanceHomework Equations Area of rectangle= side A *side B Density of a sphere= mass/(4/3piR^3) tan(θ)=opp/adj Resistance=...

Homework Statement Hello, could you please explain to me in simple terms how I can predict the chemical formula of the compounds produced when Group 7 elements are reacted with the elements in Group 1. Thanks. Homework Equations N/A The Attempt at a Solution N/A

i need help understanding compound names and formulas and charges of ions using periodic table

The question I have is if anyone knows of any book, website or thread already in the physics forums that gives a detailed but stupidly simple explanation of physics formulae and also goes into how they came to be thought up and even derived while still explaining it in basic terms. A good...

In 'AN INTRODUCTION TO SET THEORY' by Professor William A. R. Weiss, the following symbols are applied to the snippet below: ... The collection of formulas of set theory is defined as follows: 1. An atomic formula is a formula. 2. If ϕ and Ψ are formulas, then (ϕ ^ Ψ) is also a formula. ... I...

http://www.sosmath.com/trig/Trig5/trig5/trig5.html sum to product formulas part i am looking for a logical way of remmembering them

Homework Statement An electron microscope employs a beam of electrons to obtain an image of an object. What energy must be imparted to each electron of the beam to obtain a wavelength of 10.0pm? Homework Equations 1. E = hv=hc/lambda 2. lambda = h/(mv) 3. KE = .5mv^2 The...

Hi, all. I'm new with Matlab. Anyone knows how to write these formulas in Matlab? Homework Statement I need to write the following formulas in Matlab. The definitions are as follows. 1. p_{f}: the wireless link layer frame error rate 2. \tau: the wireless link layer inter-frame...

I wasn't really sure if this counted as homework because I need them in order to solve my homework problems, but since they're not my homework I'm putting them here. I need the six projectile motion formulas. I have ∆y=Viy∆t-1/2g∆t^2 (t squared) ∆x=Vix∆t I need the other four. I'd...

I was looking for help on figuring out the formulas for these questions on work and energy. Not looking for the answers, just the formula to solves these types of problems. 1. A box sits upon the floor. The box has a mass of 100. Kg. The coefficient of static friction between the box...

Question: A hot-air balloonist is ascending vertically at 1.8m/s during a burn. At the same time, a passenger drops an object from the balloon and notes that the object takes 15s to strike the ground. At what height is the balloon when the object strikes the ground assuming g=0.8m/s/s, no wind...

Homework Statement Given this formula Sum sin(a+b)=sin(a)*cos(b)+cos(a)*sin(b) prove this one Difference sin(a-b)=sin(a)*cos(b)-cos(a)*sin(b) Given this formula Sum cos(a+b)=cos(a)*cos(b)-sin(a)*sin(b) prove this one Difference cos(a-b)=cos(a)*cos(b)+sin(a)*sin(b)...

Homework Statement Two wires are tied to the 300 g sphere shown in figure. The sphere revolves in a horizontal circle at a constant speed of 6.50 m/s. What is the tension in the upper wire?What is the tension in the lower wire? Write an equation for the sum of the forces along y. Use it to...