Differential Definition and 1000 Threads

Homework Statement Solve the differential equation. -x2(dy/dx) + xy = x2y2 * sin(x) Homework Equations None. The Attempt at a Solution I first figured out that this was a Bernoulli's equation. I distributed the x2 to make it simpler. From there I divided everything by y2 to get y-2(dy/dx) +...

Hi Anyone know of an online asymmetric differential stripline impedance calculator? I already have the Saturn pcb design tool kit. I just want to find a second one to cross check the result. My experience is I have seen two calculators gave different results. Thanks

Homework Statement dy/dx = (x +y) / (x-y) , i am asked to find the first order differential equation , but the ans i gt is different from the ans given Homework EquationsThe Attempt at a Solution

Homework Statement i was given dy/dx = -(4x+4y) / (4x+4y-2) , v= x +y . I have tried to do ( as in the photo) , but I didn't get the ans , in the last line of my working , the V and x are not separable , which part of my working is wrong ? Homework EquationsThe Attempt at a Solution

I understand what is in the picture http://postimg.org/image/u5ib33kzb/ but the book goes on to say that the solution is thus of the form ## X_n = a_n sin \frac{n \pi x}{l} ## How does putting ##β=σ^2=\frac{n^2π^2}{l^2}## into (6.37) result in that?

My current understanding of differential equations is extremely shaky, and my vocabulary is probably very incorrect, but I'm curious about something I've recently seen in some Khan Academy videos (specifically this one) and in other situations with differential equations. It seems that the...

What do Physics Forums members regard as the best first introduction to differential forms ...?

Can anyone suggest a good text or a good online set of notes from which to make a first approach to the topic of differential forms ... ? Similarly a first approach to to tensors ... ? The thought is to use these notions in order to gain an understanding of differential geometry and ... later...

Homework Statement Question: Solve this differential equation dy/dt=1+y2 and y(π/4)=-1 Homework Equations The Attempt at a Solution dy/dt=1+y2 and y(π/4)=-1 dy/dt=1+y2 dy=(1+y2)dt dy/(1+y2)=dt ∫dy(1+y2)=∫dt tan-1(y)=t+c y(t)=tan(t)+c y(π/4)=tan(π/4)+c -1=1+c -2=c answer: y(t)=tan(t)-2

Homework Statement The final part of the problem I am trying to solve requires the proof of the following equation: \frac{d}{dr}(\frac{rf'(r)-f(r)+f^2(r)}{r^2 f^2(r)})=0[/B]Homework Equations I've been given the ansatz: f(r)=(1-kr^2)^{-1} leading to f'(r)=2krf^2(r)...

What does it mean when it says to classify the second-order partial differential? (See attached) How would I get started?

Homework Statement The problems are in the uploaded file. 18) satisfies the differential equation y''+p(t)*y'+q(t)*y=0 p(t) and q(t) are continuous Homework Equations Wronskian of y1 and y2 The Attempt at a Solution 18) I don't really get this one 19) Solved most but at the end, where I...

Hi, I'm trying to compute the differential decay of W boson at rest $$W^+ \rightarrow e^+ \nu_e$$ where the boson has fixed spin along z axis, and so specific cirular polarization. Using Feynman rules i get...

Homework Statement Hi. I am trying to solve a problem on renormalisation group flow and have come across the following coupled equations that I need to solve: Λ ∂g/∂Λ = b.m Λ ∂m/∂Λ = -2.m + a.g Where a and b are just constants. I need to find g(Λ) and m(Λ). Homework Equations [/B] I...

Hey guys, so my professor told me to take a look at an equation, because he thinks that there is a mistake. We are basically talking about exercise 6.3 (on last image). The pictures will show you the text, so that you have all the information, that I have http://puu.sh/mrNDl/ec19cdff63.png...

Hello everyone, I have some questions that have been bothering me for years now. Why do we use differential equations? When would I normally think about using one? What would make me use one? I know it means the slope of a function and I know the derivation/integration rules + the solution of...

Homework Statement I am trying to obtain the hermite polynomial from the schrødinger equation for a har monic oscillator. My attempt is shown below. Thank you! The derivation is based on this site: http://www.physicspages.com/2011/02/08/harmonic-oscillator-series-solution/ The Attempt at a...

Hello. I forgot the reason why 2nd order differential equation has two independent solutions. (Here, source term is zero) Why 3 or 4 independent solutions are not possible? Please give me clear answer.

Hi, I am just about to finish working through the integration chapter of calculus on manifolds, and I am wondering whether it would be better to get spivaks first volume of differential geometry (or another book, recommendations?) and start on that, or to finish calculus on manifolds first...

Simple and basic question(maybe not). How are rotations performed in differential geometry ? What does the rotation matrix look like in differential geometry? Let us assume we have orthogonal set of basis vectors initially. I am looking to calculate the angle between two geodesics. Can this...

Homework Statement Homework Equations 3. The Attempt at a Solution [/B] Hello guys,I posted images since its easier to write equations.Please can someone help me check this, if this is correct so far, then i should be able to find the velocity at C, using kinetic energy?

Homework Statement A vat with 2000L of beer contains 4% alcohol (by volume). Beer with 6% alcohol is pumped into the vat at a rate of 20L/min and the mixture is pumped out at the same rate. What is the percentage of alcohol after an hour? Homework EquationsThe Attempt at a Solution At ##t =...

When I learned differential calculus, my instructor spoke only in terms of x's & y's. I could differentiate, but had absolutely no idea what I was doing or how it applied. My mentor pulled me aside, gave me a function, f(x)=x^2, & made note that the function was modeling a vehicle's position in...

Homework Statement Find the general solution f(t) of the differential equation: f''(t) − f'(t) − 12f(t) = 36π . How many free parameters enter the solution, and why? Homework Equations f = fH + fP where fH is the homogeneous solution and fP is the particular solution. The Attempt at a...

I will be taking a first course on Quantum Mechanics and just wanted to know what kind of ordinary differential equations must i know before going into the course. Thank you!

I am taking my bachelor in geometric quantization but I have no real experience in differential geometry ( a part of my project is to learn that). So I find myself in need of some good books that cover that the basics and a bit more in depth about symplectic manifolds. If you have any...

Hello guys, I found this forum using google because I need help with simulating bungee jump model. I've already done that with zero initial values and it looks good but I want it more realistic : Let's say L is the length of rope so elasticity force starts acting when y=L so logically time...

Homework Statement Solve the differential equation: dy/dx = 2/(x+e^y) Homework EquationsThe Attempt at a Solution I tried to use the substitution v=x+e^y, but I didn't get very far: v’=1+e^y y’ v’-1=(v-x)y' y’ = (v’-1)/(v-x) (v’-1)/(v-x) (x+v-x)=2 V (v’-1)/(v-x)=2 vv’-v=2(v-x) vv’-3v=-2x...

Basically, I am confused by one question in a practice paper in which the equation is given as follows: dy/dx = e^-2y and I know the general solution is equal to : y = -0.5e^-2y + C which would make sense if it was direct integration however it seems to me it is in fact separable...

Hello, I'm trying to learn about the role that differential equations play in traffic flow, and how I can use them to model/predict/whatever you do with them with traffic flow. Do you guys know of any good and in-depth (preferably online and free) resources I can use to learn about this?

Can you advice the changes in this diff equation: $\d{y}{x}=\dfrac{y}{x^2+y^2}$

Hey! :o In what jobs is differential geometry applied and needed?

Homework Statement I need to solve the follwing differential equation $$(\frac{df}{dt}) \dfrac{4 n e^{4nf(t)}-9n e^{2nf(t)} (\frac{df}{dt})^2 + e^{2nf(t)} r^2 \frac{d^2f}{dt^2}+5n (\frac{df}{dt})^4 r^4 - r^4 \frac{d^2f}{dt^2} (\frac{df}{dt})^2}{-e^{2nf(t)}+ (\frac{df}{dt})^2 r^2}=0 $$...

So, I had studied oscillatory motion for a while and I found it unpleasant to have to remember the various different solutions for the equations of motion. I began to learn about second order linear differential equations and now I know how to solve this kind of stuff. But there is a problem...

Homework Statement ##\displaystyle (x+3)\frac{dy}{dx} = y - 2##, where x is not 3 and y is not 2. Homework EquationsThe Attempt at a Solution ##\displaystyle (x+3)\frac{dy}{dx} = y - 2## ##\displaystyle \frac{dy}{y-2} = \frac{dx}{x+3}## ##\displaystyle \int \frac{dy}{y-2} = \int...

How, if at all, would differential geometry differ between the opposite "sides" of the surface in question. Simplest example: suppose you look at vectors etc on the outside of a sphere as opposed to the inside. Or a flat plane? Wouldn't one of the coordinates be essentially a mirror while...

help to solve the differential equation у*у$^{\prime\prime}$=2х*((у$^{\prime})$^2)

Homework Statement Problem statement uploaded as image. Homework Equations Arc-length function The Attempt at a Solution Tangent vector: r=-sinh(t), cosh(t), 3 Now, I just need to reparameterize it using arclength and verify my work is unit-speed. Will someone give me a hint? Should I use...

Assume M=xdy -ydx+dz ∈ Ω1(R^3). What's the restriction of M to the plane {z=2}? I think it's xdy-ydx. Is that right?

Suppose x ∈ Ω^(n−1)(Rn \{0}) is closed and the integral of x on S^(n-1) equals to 1. I am stuck on how to show there does not exist an n − 1 form y ∈ Ω(n−1)(R^n) with y|R^n\{0} = x.

Hi, so I am just starting to learn differential equations and we were told that you have to put the equation into this form. In one of the examples in my lecture notes, which says "Solve (x^2-9)dy/dx+xy=0, x>3" He then says we need to rearrange this into the form given above, so he does this...

how dimensions of differential are made with respect to engine power and torque

Hello, I really need a good book on ordinary differential equations with applications on Quantum Mechanics, as I will be attending a course on QM but I do not have the proper mathematical background that is needed.

We have a slope, which has a M mass and a particle with m mass. There are no friction forces between the slope and the ground nor with the particle. The question is, how can i set up the differential equations to get t time. The slope has an h height and an angle of alpha with the ground...

Hey guys, I'm going to be honest and say I'm so stuck on this assignment - I really need help! I've took on a third year computational physics course last year - turn your weaknesses into strengths someone told me. Well, I failed and I'm back doing it again this year! So, I just have to pass...

i am given an equation which i have to solve in simulink. the equation is quite veered to me. some one help me in understanding what kind of equation it is so that i can solve it in MATLAB simulink. (2+x^2)theta'' + (2xx' +1)theta' + 9.8(xcostheta-sinthetha)-x''=T

Homework Statement We are given the following differential equation: $$ y+yy'-xy'=0 $$ Let's find the solution. Homework EquationsThe Attempt at a Solution So in my course usually we have to do some sort of substitution by the lines of x/y=z or y/x=z. This equation has proven...

So I have to solve an initial value problem involving the Laplace Transformation method. I have all the terms in Y(t) besides one term, I cannot figure how to change it from frequency domain back into time domain.Not sure how to type in Latex, so i uploaded a picture, using the whiteboard...

Hey guys, I'm talking to my advisor soon and I was wondering if it is typical to, after taking multi variable calc, to take differential equations and linear algebra simultaneously? I'm going to have to be taking both modern physics and organic chemistry II as well, for context. Thanks everyone

Question: Why equations x(1-x)\frac{d^2y}{dx^2}+[\gamma-(\alpha+\beta+1)x]\frac{dy}{dx}-\alpha \beta y(x)=0 should be solved by choosing ##y(x)=\sum^{\infty}_{m=0}a_mx^{m+k}## and not ##y(x)=\sum^{\infty}_{m=0}a_mx^{m}##? How to know when we need to choose one of the forms. Also when I sum over...