Value Definition and 1000 Threads

  1. S

    Momentum Conservation: How to Reconcile a Negative Value?

    Maybe a silly question but on the above question using the conservation of momentum: momentum before firing (0) = momentum after firing (55*35)+(M*2.5) If I re-range the above it's M = -(55*35)/2.5 = -770kg. I can I reconcile that minus sign (basically get rid of it)? Thanks
  2. potatocake

    Boundary value problem- Random Walker

    I want to solve this using difference equation. So I set up the general equation to be Pi = 0.5 Pi+1 + 0.5 i-1 I changed it to euler's form pi = z 0.5z2-z+0.5 = 0 z = 1 since z is a repeated real root I set up general formula Pn = A(1)n+B(1)n then P0 = A = 1 PN = A+BN = 0 -> A= -BN...
  3. tanaygupta2000

    Expectation value of momentum operator

    I know that the eigenstates of momentum operator are given by exp(ikx) To construct a real-valued and normalized wavefunction out of these eigenstates, I have, psi(x) = [exp(ikx) + exp(-ikx)]/ sqrt(2) But my trouble is, how do I find the expectation value of momentum operator <p> using this...
  4. B

    What is the value of the load resistor?

    But I think the answer is 32, is it correct?
  5. C

    B Value of G Changing Over Time?

    Hi folks, a question regarding the value of G, has there been an experimental data collected on the value of G over time, what I'm interested in, is if the value of G in the observable universe, is decreasing or increasing (by a small amount) over time, thanks.
  6. M

    MHB Distribution, expected value, variance, covariance and correlation

    Hey! :giggle: Let $X$, $Y$ and $Z$ be independent random variables. Let $X$ be Bernoulli distributed on $\{0,1\}$ with success parameter $p_0$ and let $Y$ be Poisson distributed with parameter $\lambda$ and let $Z$ be Poisson distributed with parameter $\mu$. (a) Calculate the distribution...
  7. D

    Expectation value of kinetic energy operator

    The expectation value of the kinetic energy operator in the ground state ##\psi_0## is given by $$<\psi_0|\frac{\hat{p^2}}{2m}|\psi_0>$$ $$=<\psi_0|\frac{1}{2m}\Big(-i\sqrt{\frac{\hbar mw}{2}}(\hat{a}-\hat{a^{\dagger}})\Big)^2|\psi_0>$$ $$=\frac{-\hbar...
  8. karush

    MHB Stat.02 Find the value of the new variance

    There are 8 items in a data set. The sum of the items is 48. a. Find the mean. $\qquad\textit{mean}=\dfrac{\textit{sum}}{\textit{data set}}=\dfrac{48}{8}=\textbf{6}$ The variance of this data set is 2. Each value in the set is multiplied by 3. b. Write down the value of the new mean. $\qquad...
  9. M

    MHB Value of f(1/2) using estimation for the remainder

    Hey! :giggle: Let $f(x)=e^{-x}\sin (x)$, $x\in \mathbb{R}$. a) Calculate the Taylor polynomial of order $4$ at $0$. b) Calculate the value of $f \left (\frac{1}{2}\right )$ using estimation for the remainder with an error not more than $\frac{1}{400}$.I have done question a) ...
  10. J

    A unique pointer cannot change the value of the original object?

    When I run this simple code: int main() { int x = 45; std::unique_ptr<int> q(new int (x)); *q = 3; cout << x << endl; } 45 is printed on the console. I expected this to print 3 to the console. It prints 3 when I use a built-in pointer. Does this mean that unique pointer...
  11. M

    MHB Can I Solve for c by Replacing b with a Value Greater Than 0?

    I replace b with any value greater than 0 and then solve for c. Right?
  12. berkeman

    Finding expectation value of two operators in a 3 state QM system

    A recent thread by @coolcantalope was accidentally deleted by a Mentor (I won't say which one...), so to restore it we had to use the cached version from Yahoo.com. Below are the posts and replies from that thread. The cached 2-page thread can be found by searching on the thread title, and is...
  13. M

    Value that gives more than one stationary point

    Here is my attempt at a solution I don’t know where to go from here, as the equation is a quadratic it will have two solutions which means there will be two stationary points, but I don’t know how to solve for z.
  14. U

    MHB Precalculus: What is the value of this sigma notation?

    Hi, I'm currently a Grade 11 student and I need help for this question (Precalculus): If $\sum\limits_{i=1}^{50} f(i)=90$ and $\sum\limits_{i=30}^{50} g(i)=60$, what is the value of $\sum\limits_{i=1}^{50} (7 g(i)-f(i)+12)/(2)$? P.S. To those who could answer this, it would be a great help...
  15. sahilmm15

    Find the value of ## (ax){^\frac{2}{3}} + (by){^\frac{2}{3}}##

    I was trying this problem from some 2 hours but unable to crack it. I cannot proceed after few lines i.e$${\frac{axsin\theta}{cos^2\theta}} - {\frac{bycos\theta}{sin^2\theta}} = 0$$ $${\frac{axsin\theta}{cos^2\theta}} = {\frac{bycos\theta}{sin^2\theta}}$$ $${\frac{ax}{by}}...
  16. J

    Minimum or Maximum value of a multivariate function

    First thank you for taking your time to take a look at this simple question. And sorry for the informal math language and equations, I hope you guys can understand it. So, depending on the case, I have 2 or 8 simple quadratic functions f(a), f(b), f(c),… f(z). Each a,b,c,…,z have a different...
  17. anemone

    MHB Finding Min Value of $\dfrac{|b|+|c|}{a}$ from Roots of Cubic Equations

    If $\alpha,\,\beta,\,\gamma$ are the roots of the equation $x^3+ax+1=0$, where $a$ is a positive real number and $\dfrac{\alpha}{\beta},\,\dfrac{\beta}{\gamma},\,\dfrac{\gamma}{\alpha}$ be the roots of the equation $x^3+bx^2+cx-1=0$, find the minimum value of $\dfrac{|b|+|c|}{a}$.
  18. Arman777

    Unexpected result in the numerical calculation - (invalid value encountered)

    from numpy import log as ln z = 3 k = 2 x = 1 - ln(1 + z) / ln(1 + k) y = 1/5 print("The x=", x) Q = x**y print(Q) The result is The x= -0.26185950714291484 c:\Users\-\Desktop\... RuntimeWarning: invalid value encountered in double_scalars Q =...
  19. F

    Find the value of x for which the function is discontinuous

    Could someone confirm my answer please?
  20. D.S.Beyer

    B Value of this 'Science' Channel as quick intro

    I found, what appears to be, a good channel on General Relativity and other science topics. I'm dubious because... the internet. I'd love a second opinion on whether this channels first few videos on The Maths of General Relativity are doing it justice. I'm a dad with a day job and I can't...
  21. S

    Mathematica How to Display Dynamic Values as Plain Numbers?

    In the example below, x is static while x1 is a dynamic copy of x. Also, y and z are similar expressions containing x and x1 respectively. If we evaluate expressions containing x and x1, they display in numeric and mathematical formats, respectively (y and z below). How can I display z as a...
  22. chwala

    Find the value of x using the Lambert W function

    it really took me time to figure out as to how that equation in aterisk was arrived at...i just noted that both sides of the equation were multiplied by ##-\frac {1}{3}## any particular reason for that? what is the common thinking around that? can one multiply both sides by say ##\frac {1}{6}##...
  23. kurisu

    How do I know the current's ampere value when it fluctuates rapidly?

    What "ampere value” is measured by a d-c ammeter when the current fluctuates rapidly?
  24. chwala

    Find the greatest value of argument- complex numbers

    since ##|z|≤3## →##z=0+0i##, therefore we shall have centre##(0,0)## and radius ##3##, find my sketch below,
  25. WhiteWolf98

    MATLAB How to make a while loop stop when reaching a certain value

    m_1 = 1; C_p1 = 2219; T_1in = 100 + 273.15; T_1out = 75 + 273.15; Q_1 = (m_1)*C_p1*(T_1in-T_1out); while Q_1 ~= 30000 T_1outnew = T_1out + 0.1; Q_1 = (m_1)*C_p1*(T_1in-T_1outnew); T_1out = T_1outnew; end T_1outnew keeps increasing, but the code never stops; and naturally, Q...
  26. WannaLearnPhysics

    Uncertainty of the Best Value from a Multiple-Trial Experiment

    For Example: Trial 1: 5.36 ± 0.03 Trial 2: 5.42 ± 0.04 Trial 3: 5.35 ± 0.01 Trial 4: 5.38 ± 0.03 Trial 5: 5.45 ± 0.02 What I did was take the average of the best estimates and the uncertainties. Best Value 5.39 ± 0.03 (0.03+0.04+0.01+0.03+0.02)/5=0.026=0.03
  27. U

    MHB How to find PDF and Expected value of max(x,0), for a random variable x

    Let $a,b,c, \tau$ be positive constants and $x$ is an exponentially distributed variable with parameter $\lambda = 1$, i.e. $x\sim\exp(1)$. \begin{equation} E = \tau\Big[a\frac{1+a}{1+e^{-bx+c}} - 1 \Big]^+ \end{equation} where $[z]^+ = \max(z,0)$ How can I find The PDF for $E$ The...
  28. Buzz Bloom

    I What is the best current value for Omega_r?

    The source of the 0.824×10-4 value is http://hyperphysics.phy-astr.gsu.edu/hbase/Astro/denpar.html . I also looked at the Planck 2018, paper I but could not find a value for Ωr. I searched the internet with: radiation density cosmology friedmann omega but I had no success. I also looked at...
  29. chwala

    Find the value of this definite integral

    ##\int_0^5 [-x^3+3x^2+6x-8\,]dx## ##\int_0^1 [-x^3+3x^2+6x-8\,]dx= |-\frac {17}{4}|## ##\int_1^4 [ -x^3+3x^2+6x-8\,]dx= 16## ##\int_4^5[-x^3+3x^2+6x-8\,]dx= |-\frac {49}{4}|## Therefore, total area is ##|-\frac {17}{4}|+ 16+|-\frac {49}{4}|=32.5## now where my problem is,... my colleague...
  30. N

    I How Does the Many-Worlds Interpretation Handle Expectation Values?

    I may have misunderstood the expectation value, but if not then with the Copenhagen Interpretation it is easy to understand the expectation value for a wave function. It is just based on the probability of each event. If there were 4 possible events, and the probability of the event having a...
  31. G

    MHB Interval of the Riemann integral value

    Hello everyone, I have to find an interval of this Riemann integral. Does anybody know the easiest way how to do it? I think we need to do something with denominator, enlarge it somehow. My another guess is the integral is always larger than 0 (A=0) because the whole function is still larger...
  32. S

    Find minimum value of f(x) in terms of variable a

    (1) For ##x>a## ##f(x)=x^2+x-a+1 \rightarrow## minimum value obtained when ##x=-\frac{1}{2}## Minimum value of ##f(x)=\frac{3}{4} -a## (2) For ##x<a## ##f(x)=x^2-x+a+1 \rightarrow## minimum value obtained when ##x=\frac{1}{2}## Minimum value of ##f(x)=\frac{3}{4}+a## But the teacher said...
  33. chwala

    Elementary algebra: find the value of x

    ##\frac {7}{2x+2}=\frac {4x-3}{-2x-2}## ##-7(2x+2)=(4x-3)(2x+2)## ##x^2+2x+1=0## ##x=1## or ##x=-1## can we also have; ##-7=4x-3## can the ##2x+2## cancel out? i am a bit mixed up on this very simple problem...and why am i getting false on my ti nsipre...
  34. I

    Expectation Value Notation in Griffiths QM Textbook Third Edition

    In the 3rd edition of the Introduction to Quantum Mechanics textbook by Griffiths, he normally does the notation of the expectation value as <x> for example. But, in Chapter 3 when he derives the uncertainity principle, he keeps the operator notation in the expectation value. See the pasted...
  35. K

    Find the value of Cp using SFEE and Thermodynamic equations

    I have managed to find the gamma value using the following equation: (T2/T1)= (P2/P1)(gamma-1/gamma. This will give me the answer of 1.29 SF. After this step, I am clueless. Can someone help me with this question please? I assume we have to find the enthalpy at state 1 to do that question.
  36. Z

    Boundary Value and Separation of Variables.

    If the boundary condition is not provided in the form of electric potential, how do we solve such problem? In this case, I want to use ##V = - \int \vec{E} \cdot{d\vec{l}}##, but I don't know how to choose an appropriate reference point.
  37. ?

    B Solving a RNG Problem: What is the Expected Value of N?

    Hey all, So this time I have a different kind of question - namely, "what is this called?" I recall hearing/reading this in at least two places, one of which was YouTube. The idea is the following: A RNG picks an integer uniformly from 1 to N. It picks 4. What is the expected value of N? I'm...
  38. karush

    MHB -2.4.2 interval of initial value problem

    Determine an interval in which the solution of the given initial value problem is certain to exist $t(t-4)y'+y=0 \quad y(2)=2\quad 0<t<4$ ok my first step was isolate y' s $y'=-\dfrac{y}{t(t-4)}$ not sure what direction to go since we are concerned about an interval
  39. Adams2020

    A Higgs particle and non-zero expected value in vacuum

    What does the phrase “Due to Lorentz invariance, only the Higgs particle can have a non-zero expected value in a vacuum” mean?
  40. rumborak

    I am confused about the meaning, and value, of kinetic energy

    This confusion has lingered in the back of my mind for years now, would be good for me to finally get a grasp on this. Say I have an object currently at rest, and I use energy X to accelerate it to speed v. According to the standard formula, it now has a kinetic energy 1/2mv^2. Now I use the...
  41. E

    What is the value of ω for the following wave?

    I am quite confused by this. I was sure that ω=3*sqrt(5)*10^6, because that is the coefficient of t, and generally u(x,y,z,t)=Asin(kx−ωt+ϕ) for a multi dimensional harmonic wave. However in the answers it is said that ω=3*sqrt(5)*10^14. I can't see the reason for that, could anyone explain please?
  42. AN630078

    Geometric Sequence and the Limiting Value

    1. When n=1, u1+1=3-1/3(u1) u2=3-1/3(3) u2=2 When n=2 u2+1=3-1/3(u2) u3=3-1/3(2) u3=7/3 When n=3 u3+1=3-1/3(u3) u4=3-1/3(7/3) u4=20/9 The common ratio is defiend by r=un+1/un, but this is different between the terms, i.e. u2/u1=2/3 whereas u3/u2=(7/3)/2=7/6 Have I made a mistake? 2. A...
  43. Theia

    MHB Computing the value of sine function accurately

    Hi all Simple question: How I can compute the value of \(a = \sin \left( 2017 \sqrt[5]{2} \right) \) under following assumptions: No use of advanced numerical libraries is allowed. Only accepted operations are: comparisons, absolute value, addition, subtraction, multiplication and division...
  44. anemone

    MHB Min Value of $\dfrac{a+3c}{a+2b+c}$+$\dfrac{4b}{a+b+2c}$+$\dfrac{8c}{a+b+3c}$

    Let $a,\,b$ and $c$ be positive real numbers. Determine the minimum value of $\dfrac{a+3c}{a+2b+c}+\dfrac{4b}{a+b+2c}+\dfrac{8c}{a+b+3c}$.
  45. Frigus

    B What is the RMS value in this context?

    In this text they are saying that rms value is square root of average value of i² but i am not able to relate this thing to equations they have given. It feels to me that the equations tell something different from the text. From text I interpret that if we add each and every value of i² from 0...
  46. A

    How to Find the Minimum Angle Value Involving Two Variables and Constraints?

    I tried to do it by derivative but there are two variables, so I don't know how to proceed. Does anyone know how I can solve it? Remembering that you don't need to find the value of ##\theta##. I just need to find a relationship between ##\theta_1## and ##\theta_2##
  47. nomadreid

    I Ratio of a real value to the max theoretical value: what term to use?

    If the Summary is not clear, the following is an example translated from: https://telecombloger.ru/7335 '... air conditioning systems. For example, the efficiency of a compressor is about 85%. The remaining 15% is spent on friction, oil movement, overflows, heating, etc. The efficiency of the...
  48. I

    Calculate Equilibrium Constant for Polyprotic Acid Reaction

    The principal equilibrium in a solution of NaHCO3 is HCO3-(aq) + HCO3-(aq) <-> H2CO3(aq) + CO32-(aq) Calculate the value of the equilibrium constant for this reaction. My solution: This overall reaction is the same as the sum of the following reactions: HCO3-(aq) <-> H2CO3(aq) + OH-(aq)...
  49. S

    Hypothesis test: Find the critical value of Z, Zc

    Question: The national price of a good is distributed normally with mean £1.20, standard deviation 5p. Sample data is for price in London, determine whether there is sufficient evidence at 5% level to suggest that the mean price in London is different to the national mean. Standard deviation...
  50. B

    I Muon Time Dilation in Accelerating Frames

    Hi In the book, "Why does E= mc2" by Cox and Forshaw, while discussing time dilation, the example of a muon is given. The authors explain that muons when circulated in the 14 m diameter AGS facility at Brookhaven at 99.94% of the speed of light, its lifetime is increased from the value of 2.2...
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