equations Definition and 72 Threads

Hello! I considered connections between spacetime intervals in 2D (see pic below) and their coordinates/times. I derived following equations (##A_1## and ##A_2## are coefficients that depend on coordinates and times): ##A_1(x_1,x_2,t_1,t_2)(c^2\Delta t^2-\Delta x^2) =...

do we have laws of nature discovered that form a set of equations which use different formula in different set of parameters?

So far as I can tell the normal way to write inline equations in mathJax is to surround the mathematical code by single dollar signs, or in the case of this site pound signs #. However, this never seems to work. Surrounding the code by double signs for centering and setting apart the equations...

Was looking for some help on my differential equations homework and found the exact problem which really helped, but the answers stopped halfway through, and I can't figure out how to solve the second half lol

I was reading about how Sirius A and B were part of a binary star system, im familiar with the concept of binary star systems and even a little bit of how they discovered, as well as spectroscopic and eclipsing binary star systems. However, I still dont know how to calculate period or just...

TL;DR Summary: Books that reflect: https://web.williams.edu/Mathematics/lg5/Rota.pdf I'm looking for a book or course that distills the subject of differential equations (DE) according to these 10 points : https://web.williams.edu/Mathematics/lg5/Rota.pdf I'm a part-time student working...

In Maxwell's equations, the electric field appears in both Gauss's Law and Ampère's Law. Do these refer to the same electric field, or are they different components of the overall electric field? I think Gauss's Law gives electric field 1 and Ampère's Law gives electric field 2. So the total...

I was thinking of writing a motivational essay for physics undergrads where I provide a list of equations which have the property of telling you when you mastered (at undergraduate/early graduate level) a field of physics. Here are some examples: Electromagnetism: ##{\partial}^2 A^{\sigma} =...

$$\Delta G_{vap}=G(g,P)-G(l,P)\tag{3}$$ $$=G^\circ+RT\ln{\left ( \frac{P}{P^\circ }\right )}-G(l,P)\tag{4}$$ The Gibbs free energy of a liquid is almost independent of pressure, so we use the approximation that ##G(l,P)\approx G(l,P^\circ)=G^\circ(l)##. Then $$\Delta...

Mentor note: Moved from technical math section, so missing the homework template filling in the boxes is easy, 1,3,6,10,15 second is just squares of that, 1,9,36,100,225 But how I anyone supposed to find and expression for this? This is from a textbook on elementary algebra, the specific...

Since I understood that torque = net moment, and as it said angle from the vertical, I used the equation t = F*d*cosx. So, 6 = 40*0.4*cosx, x = 68 degrees. I got a zero out of 5 in this question because the thought process was wrong as well as the answer. I do not understand this problem beyond...

Hello, I came across the question attached. To approach this, I assigned S1 to car Y and S2 to car X. So the displacement of Car Y is S1=S2 + d(naught). Then using S1= ut+(1/2) at^2 for car Y and S2= uT , I got to uT + d(naught) = VT + (1/2)aT^2. However, I am stuck here as I can't relate...

x=x0=vt v=v0+at x=x0+v0t+(1/2)at2 That (1/2) there does not make sense to me. It makes sense mathematically, if you integrate the velocity formula you get the (1/2) as a result of the integration rules and if you differentiate its needed to cancel out the 2 and arrive at the velocity...

I am looking at this link; https://tutorial.math.lamar.edu/Classes/DE/RealRoots.aspx ##y{''} +11y{'} +24 y=0, y(0)=0, y^{'}(0)=-7## Now the general approach of applying boundary conditions directly is quite straightforward to me. I am interested in using an alternative approach, that is the...

I've had Mathematica for a long time, but up until now, I just used to use the free-form input. I'm trying to learn the language so that I'm able to do more with the software. However, the information I gather from the Wolfram site is worthless for a lot of things, as I don't understand what...

I'm trying to graph two equations to compare the two visually. For some reason, one of them isn't showing up, even though I'm in a range to where it should be. See the screenshot below. The "3x - y = 4" is graphing fine, but for some reason, "x + y + z = 5" isn't showing up. At first, I...

I've worked my way through this exercise but I am a bit puzzled by the last line "What do the choices ##\mathcal H = -½, 0, -½\mu^2, +½ ## mean for the geodesic and the choice of parameterisation?" I've worked to produce: ##\big (\frac {dr}{d\lambda} \big ) ^2 = E^2 - \big (1- \frac {2M}{r^2}...

To find the time of this problem, I used the equations 3 + (10 * x ) = 13.5 *x. 3 = 3.5*x. Therefore x was 0.857. To start off with child A was already three feet above ground and I got the answer to the time. However I couldn't find the height.

I am interested what are main differences/news in two Claude Navier works "Sur les lois des mouvements des fluides, en ayant égard à l’adhésion des molecules"- memoire 1 and "Sur Les Lois du Mouvement des Fluides" memoire-2? Are both works written(not published) in 1821? Does memoire 1...

I noted that, ##lcm(a,b)=2048## Letting ##a=2^x## and ##b=2^y##, ##⇒\dfrac{1}{2^x}+\dfrac{1}{2^y}= \dfrac{3}{2^{11}}## ##⇒\dfrac{2^{11}}{2^x}+\dfrac{2^{11}}{2^y}= 3=[4-1]## ##⇒\dfrac{2^{11}}{2^x}+\dfrac{2^{11}}{2^y}=2^2-2^0## My intention being to write all the numbers to base ##2##...

Hello, can anyone tell me about applications of Diophantine linear equations to physics?The only example that comes to mind is that of a series of weights. I have a measuring rod that is 40cm long and hinged in the middle. If I put a 40g weight at one end, how can I place 5g, 7g, 11g, 13g, 17g...

By the First Law, Definition of an Adiabatic Process, and Definition of Work: ##\Delta E = Q - W = - W = - P \Delta V ## (because ##Q = 0##) (Equation 1) By the Equipartition Theorem: ##\Delta E = \frac{3}{2} Nk \Delta T ## (Equation 2) By Setting Equation 1 equal to Equation 2 ## \Delta T...

Ok I need to clear up a few things. First, in (Figure 1), a soccer ball (the circle in the photo), would have the magnus force towards the lower pressure because the universe favors high entropy? Also what are the forces are active in figure 2? Lastly what to the variables in Figure 3 mean...

For this problem, Does someone please know how they combined the two equations for H to get the finial equation ##H(x,y) = .... = c##? Thanks!

For this problem, Would it not make sense to use for ##x' = -sx - gx - ry## as a better version of ##x' = - gx - ry## since the ##sx## term connects the two DEs to form a coupled system (from what the author explains the ##sx## term represent insulin glucose transformation). Thanks!

For this problem, The solution is, However, can someone please explain to me where they got the orange coefficient matrix from?It seems different to the original system of the form ##\vec x' = A\vec x## which is confusing me. Thanks!

For this problem, Can someone please explain to me how they got from the orange step to the yellow step? I am confused how the two expressions are equivalent. Thanks!

Hello, can anyone give me a hand? I am trying to make a post but the LaTex engine doesn't work properly. I Try the `four dollars´ and the `four hashtag´ method on, but the equations dont appear when I click the Preview button. The LaTex engine doesn't do anything. I have posted several threads...

Hello I am trying to figure out the equations of motion for the following scenario: a mass m is held upright on by a massless rod mounted on a cart that is being pulled by a linear force. The caveat is that the rod is mounted on the cart via a torsional spring which causes a restorative torque...

Fx = 0 = ABcos(a)+BCcos(b)-BDcos(30) Fy = 0 = ABsin(a)+BCsin(b)-BDsin(30) == Fx = 0 = ABcos(a) + 3.2737cos(b) - 3.738 Fy = 0 = ABsin(a) + 3.237sin(b) - 2.158 But i cant find a third equation to use. I've tried a+b = 90 but that produced a number of errors. Thank you. Edit: angle b is the...

solution; @Mark44 we discussed this sometime back on the forum. The approach of using determinant or echelon form of a matrix was sufficient. Would i be correct to use this approach, ##x+2y+3z=4x+5y+6z## ##3x+3y+3z=0## and ##7x+8y+9z=x+2y+3z## ##6x+6y+6z=0## Then, it follows that the...

I recently finished a website and I'd like to share it in case it would be useful, as well as to get feedback. The URL: equationvisuals.com The website uses a basic computer algebra system (CAS) I built to solve systems of equations and show its steps. These equations can then be linked to...

Video Link Many thanks if you can guess what the name of the software is. It can be very useful for teaching. Let me also confess that, till date, I haven't found a software that can type ##\rm{LaTeX}## equations in real time on to the computer screen. LyX is the only one I know of, but the...

Two simple equations, yet I can't find any sources that explains it very well. If you have any suggestions on where I could find this then please link them! $$ \Delta{t'}=\gamma(\Delta{t}-\frac{v}{c^2}\Delta{x}) $$ Does it matter if S' is moving away to the right, or to the left, of S? I...

From the forces equation I can only understand from it that the forces' equations are:##N=Mg## and ##T\sin \theta=m\ell \ddot{\theta}##. But I don't know how to find the Torques' equations. Any help is appreciated. N=Mg ##Tcos⁡θ+N=mg

So if Maxwell's Equations state that Div B = 0 which is a statement that there are no magnetic monopoles why do some folks claim that Cosmic Inflation "dilutes" magnetic monopoles?

I am interested in a more direct linear equations approach...to solve, which i know is possible... A. My initial thinking was along the lines, let ##x## be the amount that Arjun paid in 2018 and let ##y## be the amount that Gretal paid in 2018 where A was the total amount paid in 2018 ...

Does this equation mean that: ## x+y =z ##, and ## x = y##? I mean ## \delta_{ij} ## terms in the LHS of the eqaution equal those at the RHS ? with knowing that ## \partial_i \partial_j x ## term dose not vanish for ## \delta_{ij}=1 ## Any help is appreciated!

I'm not sure how to go about solving this mathematically? In just using what seems obvious, I know the angle pi would work, because pi = -1, and 2pi = 1. However, as far as manipulating the equations in a way where it can solve itself without me having to look at a chart where cos for both x...

Consider the Heisenberg picture Hamiltonian $$H(t) = \int_{\textbf{r}}\psi^{\dagger}(\textbf{r},t)\frac{(-i\hbar\nabla+e\textbf{A})^{2}}{2m}\psi(\textbf{r},t)$$ where ##\psi(\textbf{r},t)## is a fermion field operator. To find the equations of motion that ##\psi,\psi^{\dagger}## obey. I would...

This is fine but i have my own approach as follows; ##\begin{pmatrix} -7 & -6 & -12 & -33 \\ 5 & 5 & 7& 24 \\ 1 & 0 & 4 & 5 \end{pmatrix} ## → Row 1 times 5 and row 2 times 7... ##\begin{pmatrix} -35 & -30 & -60 & -165 \\ 35 & 35 & 49& 168 \\ 1 & 0 & 4 & 5 \end{pmatrix}## →...

I got c=13, but I'm using an app that, at the 'diagnostic' stage, doesn't tell you if you're correct or not (I multiplied the first equation by 4, and the second by 2, then subtracted the second from the first)

Hello, I am looking for a detailed derivation of the equations used to generate the modified sine curve. I found one in Cam design handbook by Harold A. Rothbart but I didn't understand how we get certain equations. My end goal is to combine the modified sine curve with constant velocity and get...

I have the matrix relationship $$C = A^{-1} B^{-1} A B$$ I want to solve for ##A##, where ##A, B, C## are 4x4 homogeneous matrices, e.g. for ##A## the structure is $$A = \begin{pmatrix} R_A & \delta_A \\ 0 & 1 \end{pmatrix}, A^{-1} =\begin{pmatrix} R_A^\intercal & -R_A^\intercal\delta_A \\ 0 & 1...

Can anyone guide me how can I find ##C_P## and ##C_V##? There are two equations in my book which I think can help but I'm not sure if I can use them to find ##C_P## and ##C_V## of a vander waals gas. I know equation of state of this gas.

I tried using conservation of energy, and using the equations for circular motion, but I can't seem to find a solution. Any help?

Been dipping my toes into maths by examining how equations work on the most basic level, and I love encountering equations that turn out to model similar aspects in nature, for example the inverse square law is apparent in equations for gravity and for electromagnetism. In the thumbnail of...

Just going over some basic equations to help someone out and i have noticed that i get 2 different answers when using 2 different but very similar equations for impulse. first eq. I=F*t lets say that i have a small rocket motor that has a force of 5.95 newtons and a impulse of 2.5 n-s...

I tried using these equations, but it's not clear if we should hold y_1 = y_2. A transverse velocity vector would produce a flow at some angle to the horizontal, but How do they known there's such a vector?