Manipulation Definition and 192 Threads

For example, let's say the quadratic curve ax^2 + bx + c intersects the x-axis at x=-5, x = 3 Why is it we can say the equation of the curve is then (a)(x+5)(x-3) ? how does this manipulation come about, in particular, the (a) coefficient. Why can we just slot (a) into the factors (x+5)(x-3) ...

Hi all, I am starting with the following equation: ##2\cot\left(\frac{\theta}{2}\right) = \cot\left(\frac{k_{1}}{2}\right) - \cot\left(\frac{k_{2}}{2}\right)## with the following definitions: ##k_{1} = \frac{K}{2} + ik, k_{2} = \frac{K}{2}-ik, \theta = \pi(I_{2}-I_{1}) + iNk##, where...

I’ve read that the Ca2+ channels in neurons can be manipulated through the use of certain radio wave frequencies. And the resulting internal/external charge differential will cause the neurons to fire. Does anyone have any more insight into that?

I have about one hundred folders. Each folder has both .jpg and .mp4 files. I want to delete all the .jpgs but not the .mp4s. I don't want to do each folder by hand. Does anyone know the Windows/DOS command that will do this. Just moving the files depending on file type is enough.

I'm just playing around with circuitry, working with manipulation of Audio Signals in active circuits(My guitar, going to build an internal preamplifier). I've been trying to find an answer on this all day with no luck. As eager as I am to see what the effect would be it would be nice to know...

If I have an equation, let's say, $$\mathbf{A} = \mathbf{B} + \mathbf{C}^{Transpose} \cdot \left( \mathbf{D}^{-1} \mathbf{C} \right),$$ 1.) How would I write using index notation? Here A is a 4th rank tensor B is a 4th rank tensor C is a 3rd rank tensor D is a 2nd rank tensor I wrote it as...

Property (a) simply states that a second rank tensor that vanishes in one frame vanishes in all frames related by rotations. I am supposed to prove: ##T_{i_1 i_2} - T_{i_2 i_1} = 0 \implies T_{i_1 i_2}' - T_{i_2 i_1}' = 0## Here's my solution. Consider, $$T_{i_1 i_2}' - T_{i_2 i_1}' = r_{i_1...

Attached is a pic of the page in the book: My problem is with equation (11.34) specifically with the term ##\frac{6M^3}{L^2}y## I get ##L^4## instead of ##L^2##. Here are my calculations (I also checked it with maple's expand command)...

How do I write the following expression $$\epsilon_{mnk} J_{1n} \partial_i\left[\frac{x_m J_{2i}}{|\vec{x}-\vec{x}'|}\right]$$ back into vectorial form? Einstein summation convention was used here. Context: The above expression was derived from the derivation of torque on a general current...

##(\frac {∂p} {∂ρ})_s=ϒ(\frac {∂p} {∂ρ})_T## The variables are p for pressure, ρ for specific mass density and γ is ratio of specific heats. I am able to show that the relation is valid for a perfect gas but cannot show its validity in general. The closest I get is ##dp=(\frac {∂p} {∂ρ})_s...

For instance, using the vector ##A^\alpha e_\alpha##: ##g_{\mu \nu} e^\mu \otimes e^\nu (A^\alpha e_\alpha) = g_{\mu \nu} (e^\mu, A^\alpha e_\alpha) e^\nu ## ##g_{\mu \nu} e^\mu \otimes e^\nu (A^\alpha e_\alpha) = A^\alpha g_{\mu \nu} \delta_\alpha^\mu e^\nu = A^\mu g_{\mu \nu} e^\nu = A_\nu...

The solution is as follows : The substitution is what nags me , which is as follows : This substitution "trick" to me seems impossibly difficult to arrive at "logically" without pretty much reverse engineering the problem. So is this simply a lack of practice/ familiarisation showing ? I feel...

εikl εjmngkmMkn = εikl εjknMkn = (in book it changed sign to -εikl εjknMkn - Why? ) By identity εikl εnjkMln = (δinδkj - δijδkn)Mkn = ? I then get .. Mji - δij Mnn ( is this correct ?) There 's more to the question but if can get this part right, I should be able to complete the...

I substituted and got ((xn/2nn!) + 1)/(xn/2nn!). I then multiplied by 2nn! to each side and got (xn + 2nn!)/(xn). Now I am confused as to what my next step should be.

Summary: Mathematical and Physical queries in regards to Electromagnetic Fields and their manipulation of Space-Time. I recently started looking into Einstein's Field Equations, to get a better understanding of how mass distorts and curves the plane of Space-Time, however from doing this I...

Hello I hope someone can help me, as i am kinda stuck for the moment. As you can see, the assignment states that I need to find the poles from the closed loop transfer function. I plan on doing so, by using block diagram reduction method. This is as fare as I've come, and can't come...

Hello I hope someone can help me, as i am kinda stuck for the moment. As you can see, the assignment states that I need to find the poles from the closed loop transfer function. I plan on doing so, by using block diagram reduction method. This is as fare as I've come, and can't come further...

Hi I am trying to learn how to manipulate 3D files like obj or stl using programming (I primarily use Python, but also know Javascript). Which resources can I use to learn this?

Hello! In the picture below, i can't seem to understand how they get from the first line, to the second line. (https://imgur.com/a/Fal3T) When i write it up as dr/dT on the leftside, and separate the r's and the T's, i get dr/((1/2)*r-(1/16)*r^5)=dT which is not the same as in the...

Hi. If we want cell to accept vector dna in transformation, we treated with calcium chloride or chilled on ice etc.. But i have a trouble with one issue about that. Books say that ; We must choose the vector that specific according to the cell that will do transformation. But we will treat with...

Homework Statement 1. Calculate the electric field at field point 3i + 6j created by a 5.50uC electric charge at 13i + 8j 2. Calculate the electric force on an electron at field point 3i + 6j and in the same electric field calculated for the prior problem. Homework Equations The Attempt at a...

In the thread https://www.physicsforums.com/threads/first-human-embryos-edited-in-u-s.921238/ the film Gattaca was discussed as an example of a very bad society brought about by the use of human genetic manipulation. In my opinion the Gattaca society is a very poor example of this in that is is...

I am working on a story where superheroes have started to appear. Their powers are all based on manipulation of spacetime and mass, and not on electromagnetism. One character is a speedster who can compress time. He can experience many seconds while everything around him experiences one...

I live in the upper Mississippi valley, near the boundary intersection for the states of Wisconsin, Iowa, and Illinois. It is a very rare day that I cannot see several, sometimes many, very high altitude con trails in the sky. The usually progress roughly NE across my area, although this morning...

I know that the Dirac equation is ##i\gamma^{\mu}\partial_{\mu}\psi=m\psi##. How do I use this to show that ##(\partial_{\mu}\bar{\psi})\gamma^{\mu}=im\bar{\psi}##?

Hi, I am having a real senior moment and can't quite get my head around a physics problem. I need to split an equation into two parts, in turn creating a coefficient and my mind has gone totally blank! I need to split the Maxwell-Boltzmann distribution formula from: f(v) =...

Homework Statement Converting the simple pendulum expression for g in terms of the angular frequency ω instead of the period T, where ω=2π/T, yields g=ω2L. Derive an expression for the error (Δg) in g by first setting g=A⋅B. A= B= Therefore in terms of A, ΔA, B, and ΔB: Δg/g= Converting back...

Homework Statement This is a general question that applies to many homework problems (and real world problems), but I will provide an example to help guide the discussion. I am hoping you all can give me some examples of particularly clever manipulations of Maxwell's equations to make a...

Hi I'm trying to give myself a refresher in Leaving Cert maths and I'm running through some problems. Here's one which has me stumped (sorry I can't figure out how to show the actual symbols on the post, it's just showing as raw LaTEX when I try ) Combine terms and simplify the expression of -...

Does anyone know if there's any q-switching technique that makes use of an unstable resonant cavity (or some kind of switching of the cavity between stable and unstable) to achieve the pulse output?

Homework Statement If x=2+2^1/2+2^2/3. Then x^3-6x^2+6x=? Homework Equations (A+b+c)^2=a^2+b^2+c^2+2(ab+bc+ca+) The Attempt at a Solution x^2= 6+3(2^2/3)+2^4/3+4(2^1/3)[/B]

Homework Statement I have this Doppler effect formula, but I don't know how it was derived, I can't repeat the process myself to solve for speed of the source, I would really appreciate if someone could mathematicly solve this in steps, thank you very much. Homework Equations...

Homework Statement Hello, I'm not trying to solve this exact problem although mine is similar and I am confused on how they were able to get a -1 in the exponent from one step to another. Homework Equations I have attached a picture indicating the step that I am confused about. How are they...

Can a Markov chain be used to generate a set of qubits given their initial state?

I was looking over my lectures notes and became stumped when the lecturer began manipulating an integral using a dummy variable. I've attached the integral below as a JPEG. I can follow the substitution up until the very end but am having trouble understanding why he replaced u with a positive s...

The Gordon identity allows us to solve using $$2m \bar{u}_{s'}(\textbf{p}')\gamma^{\mu}u_{s}(\textbf{p}) = \bar{u}_{s'}(\textbf{p}')[(p'+p)^{\mu} -2iS^{\mu\nu} (p'-p)_{\nu}]u_{s}(\textbf{p}) $$ But how would we solve for $$2m \bar{u}_{s'}(\textbf{p}')\gamma^{\mu}v_{s}(\textbf{p}) $$ Would a...

With the upcoming gravitational waves discovery , after we study their practical aspect enough , will we ever be able to manipulate gravity or something as such ? What exactly are the major benefits of this discovery . It ''opens a window for physics'' but what exactly this implies besides the...

Homework Statement Write a program that reads data about n number of books. Sort data about books lexicographically by title (if the title is the same, sort by publish year), and then for every book sort data about authors. Then, read name and surname of one of the previously read authors, and...

I am interested in track & have found through some hard work that for 800 that 1'42.00 is same value as for 3'44.00 for 1600 ( note : for 1600m not 1 mile ) It is a Log relationship but I can't quite settle on what the value for equivalence should be for 1500m. I have a provisional figure of...

Homework Statement By considering the power series (good for |x| < 1) ##\frac{1}{1-x} = \sum_{n=0}^\infty x^n = 1 + x + x^2 + x^3 + x^4 +...## Describe how to manipulate this series in some way to obtain the result: ##\sum_{n=1}^\infty nx^n = \frac{x}{(1-x)^2}## Homework Equations Maclaurin...

A presumably basic introductory equation manipulation in 2-d conformal field theory. How does from (when the metric is Euclidean) follow The right equation is clear (the metric is zero for different indices). But how do i get to the first equation on the left? thank you

Homework Statement Homework EquationsThe Attempt at a Solution I don't know if I am just stupid, but I can't see how to make this manipulation. I tried factoring the denominator $$ g_{p} = \frac {-1.43}{(s-1.399)(s+5.086)} $$ Then take out -1.399 and 5.086 $$ g_{p} = \frac...

Hi All, I've been stuck on a problem and after much simplification, it has been reduced to the following: Is it possible to factor out the (a^2 - b^2) bit. For example, if a = b, the equation would not be valid. Is there any way to factor it out using manipulation? Best wishes, 'nap

Hello there, I was wondering if someone might be able to help me out with some intermediate steps please. I can't see how $$f_{tt} =-\int_{r_0}^0 \left(\frac{2Gm_0}{r} - \frac{2Gm_0}{r_0}\right)^{-\frac{1}{2}} dr$$ becomes $$f_{tt} =-...

Homework Statement In an experiment to study a black body radiator, the intensity of emitted radiation is measured as a function of the wavelength of the radiation. At a particular temperature T1 the wavelength of the highest intensity radiation is determined to be λ1. When the temperature is...

I'm trying to integrate a function in a classical physics problem but when I apply the limits it gave undefined results. Hence, I looked up that particular part of the solution and I did not fathom the function manipulation. It states that if x≤b in the following expression...

So my textbook definitions of the ricci tensor and ricci scalar are: ##R_{ab}=R_{acbd}g^{cd}## - I note the contraction is over the 2nd and 4th index. and the 1st and 3rd. ##R=R_{ab}g^{ab}## Now, I'm trying to show that...

1. T^2 = (4 pi^2 m)/k * d^2 + (4 pi^2 I)/k y = m * x + c Information (4 pi^2 m)/k = m (gradient) (4 pi^2 I)/k = c (the y intercept ) A graph of T^2 vs d^2 was plotted. (^2) means squared Find constants k and I How is this done since the m in the...

Do you know any good software for manipulating tensors: varying Lagrangians, checking gauge and supersymmetry transformations, etc. ? One that could deal with anti-commuting variables would be good too. One that also supplied group constants for SU(n) etc. would also be useful. I was also...

I am making mess of the following expression.. i have following expression ## \frac{\partial{g}}{\partial{g_{\mu j}}} *g_{\nu j}=g \delta^{\mu} _{\nu} ## then I have sum over j only in the above expression. But above expression is nonzero only when ##{\mu}## is equal to ##\nu##. So we have ##...