fractional Definition and 221 Threads

  1. Euge

    POTW An Integral with Fractional Part

    Evaluate the integral $$\int_0^1 x\left\{\frac{1}{x}\right\}\, dx$$ where ##\{\frac{1}{x}\}## denotes the fractional part of ##1/x##.
  2. Mustafa Bayram

    B Is there a fractional frequency of light?

    If emw spectrum is continuous, possible wavelengths should be infinite and there should be fraction of frequencies like 25,2 hertz. Well is there a fractional frequency of light? In high school when we are teaching interference of light we say "only the same wavelength of lights interfere with...
  3. chwala

    Solve the given equation that involves fractional indices

    The actual problem that i was looking at with my students was supposed to be ##x^\frac{2}{3} - x^\frac{-2}{3}-6=0##(which is easy to solve using quadratic equations) of which i wanted them to solve, ...then i realized then that i had erronously posted ##x^\frac{2}{3} - x^\frac{-3}{2}-6=0## on...
  4. M

    A Peebles Equation for fractional electron density

    I am trying to compute the Peebles equation as found here: I am doing so in Python and the following is my attempt: However, I'm unable to solve it. Either my solver is not enough, or I have wrongly done the function for calculating the Equation. # imports from scipy.optimize import fsolve...
  5. archaic

    Solving for a variable in an equation with fractional powers

    I have tried manipulating this to $$1-\frac{8}{(\pi k_B T)^2}\mu^\frac12(\epsilon^\frac32-\mu^\frac32)=0\Leftrightarrow\left[1+\mu^\frac12(\epsilon^\frac32-\mu^\frac32)\right]^{-\frac{8}{(\pi k_B T)^2}}=0$$ but this doesn't seem to lead anywhere. any hints please? the solution is one of these...
  6. V

    B Determine a fractional square root without calculator

    I have to solve a certain numerical problem without using calculator and furthermore, there is a time limit for solving this problem. The answer I have got so far is ## \sqrt{\frac{100}{99}}## I know I can reduce the numerator to 10 but then I am stuck with square root of denominator which is...
  7. anemone

    MHB Find Fractional Part of $(p+1)!/(p^2)$

    Let $p$ be a prime number. Find the fractional part of $\dfrac{(p+1)!}{p^2}$.
  8. Kaguro

    Fractional increase of energy vs momentum with relativity

    My attempt: ##E^2 = p^2c^2 + m_0^2c^4## ##2E dE = 2pc^2 dp ## ##\frac{dE}{E} = \frac{pc^2}{E^2}dp=\frac{p^2c^2}{E^2}## % (dp/p = 1%) ##=\frac{E^2-m_0^2c^4}{E^2}## % ##=1-\frac{m_0^2c^4}{E^2}## % ##=1-\frac{m_0^2c^4}{m^2c^4}## % ##=1-\frac{1}{\gamma ^2}## % ##=\frac{v^2}{c^2} ##% =0.81...
  9. mcastillo356

    B Limit of a function raised to a fractional power

    Hi, PF This is the quote: "If ##m## is an integer and ##n## is a positive integer, then 6. Limit of a power: ## \displaystyle\lim_{x \to{a}}{\left[f(x)\right]^{m/n}} ## whenever ##L>0## if ##n## is even, and ##L\neq{0}## if ##m<0##" What do I understand? -whenever ##L>0## if ##n## is even: ##m##...
  10. evinda

    MHB Solving the Fractional Knapsack Problem - Wave and Thinking

    Hello! (Wave) I found the following algorithm for the fractional knapsack problem. Why at the case else, we do not change the variable w to w+(W-w)/S.weight? (Thinking)
  11. A

    Powers with fractional exponents that have an even denominator

    (If I should have posted this in the Math thread instead of the Homework thread, please let me know.) I have three questions which I will ask in sequence. They all relate to each other. I've typed my questions and solutions attempts below. I've also attached a hand-written version of this...
  12. hackedagainanda

    Why do fractional exponents result in the square root operator?

    So I got the answer through a little addition i.e 9^(1/2) multiplied by 9^(1/2) = 9^1 or 9 3 x 3 = 9 so 3 is the answer to what is 9^(1/2) I've tested this out with a few other numbers and have made this generalization, x^(1/2) = √x It seems to make the equations orderly and consistent but is...
  13. aspodkfpo

    Fractional Errors: When to Use Raw vs. Fractional Values?

    Why do fractional errors have a different error value from subbing in the raw values? e.g. 10 +- 1 divided by 10 +- 1 fractional error yields 20% 11/9 - 9/11 yields 40/99 In cases like these do we use the original values and attempt to find the maximum error distance or use fractional errors?
  14. S

    A Fractional Calculus - Variable order derivatives and integrals

    Does anyone know any good research on this topic? I'm basically looking for information on what would be solving integral and differential equations in which the unknown you need to solve for is the level of a integral or derivative in the equation. For example F'1/2(u)+F'x(u)=F'1/3(u) where the...
  15. Physics lover

    No. of positive integral solutions of fractional functions

    I know how to find integral solutions of linear equations like x+y=C or x+y+z=C where C is a constant. But I don't have any idea how to solve these type of questions.I am only able to predict that both x and y will be greater than 243554.Please help.
  16. benorin

    I Fractional Integral of which function is equal to Riemann's Zeta-Function?

    So the problem I’m attempting to solve is ##\lim_{x\to a} I_{\alpha}f(x)=\zeta (\alpha )## for f, and a, where ##\zeta (\cdot )## is the Riemann zeta function and ##I_{\alpha}## is the Riemann-Liouville left fractional integral operator, namely the integral equation $$\lim_{x\to...
  17. Kaushik

    What exactly is fractional distillation?

    Could someone please explain fractional distillation? I find it really confusing to understand. Thanks!
  18. E

    B Resolving index laws for fractional exponents

    I was just thinking about this earlier and couldn't come up with a good enough resolution. I'm guessing it's a matter of convention more than anything. If we have ##x^{2} = a##, taking the principle root of both sides gives ##\sqrt{x^{2}} = \sqrt{a} \implies |x| = \sqrt{a}##. Yet evidently if...
  19. D

    I Odd/even functions and fractional indices

    Hi. I would like to check that my understanding is correct. For ##f(x)=x^{1/n}## where n is an integer. If n is odd then f(x) is an odd function while if n is even then f(x) is neither odd or even as it involves the square root function which is only defined for non-negative x. For ## f(x) =...
  20. binbagsss

    A Fractional Quantum Hall Effect- degeneracy of ground state (Tong's notes)

    Hi , I'm looking at the argument in David Tongs notes (http://www.damtp.cam.ac.uk/user/tong/qhe/three.pdf) for ground state degeneracy on depending on the topology of the manifold (page 97, section 3.2.4). I follow up to getting equation 3.31 but I'm stuck on the comment after : ' But such an...
  21. M

    Find the fractional increase in inertial mass when an ice cube melts

    Summary: Apparently an ice cube gains mass when it melts So I'm asked to "Find the fractional increase in inertial mass when an ice cube melts ". All I've got off the top of my head right now is that a cube has energy = mc^2, and then when the cube melts, energy Q = (Heat of fusion)(m) is...
  22. Mcp

    Phase diagrams for fractional distillation

    https://www.chemguide.co.uk/physical/phaseeqia/idealpd.html#top I learned about phase diagrams involving partial Vapour composition, temperature and composition of binary solutions from this website. You can find it if you scroll down to a little above the end First it considers a binary...
  23. jk22

    A Fractional spacetime, dimension equation

    Suppose we use fractional derivatives (https://en.m.wikipedia.org/wiki/Fractional_calculus) in GR, hence we have a local group symmetry ##SO(3-\epsilon,1+\epsilon)## does any reference exist about an equation for ##\epsilon## ?, since it could depend on coordinates too.
  24. U

    Simplifying fractional indices

    $$10π \left( \frac V {4π} \right)^{2/3} = 5\sqrt[3] {{V^2}\frac π 2}$$Not sure how to deal with the $$10π$$ and how we get $$\frac π 2$$.
  25. M

    Fractional polynomial addition

    Homework Statement Determine whether there exist ##A## and ##B## such that: $$\frac{1}{3x^2-5x-2} = \frac{A}{3x+1} + \frac{B}{x-2}$$Homework Equations None The Attempt at a Solution [/B] First I divided the polynomial ##3x^2-5x-2## by ##3x+1## and got ##x-2## as a result without a...
  26. A

    Can More Readings Reduce Fractional Error in Measurement?

    Why is fractional uncertainty not affected by systematic error? For example à vernier calipers measures the diameter of a coin: (5.06+-0.04) mm Can taking more readings, say 6, and taking average, reduce fractional error?
  27. J

    Fractional Flow Reserve and the physics behind it

    Have been referring to this forum a lot and I think I finally understand it. However I couldn't find a discussion specific to applying the Laws of Ohm, Poiseuille and Bernoulli's to why we use a pressure wire to study coronary blood flow through a lesion site in the coronary artery. So I made...
  28. Jozefina Gramatikova

    Fractional uncertainty of g on the surface of the Sun

    Homework Statement Homework Equations The Attempt at a Solution it looks like I got too big numbers for the uncertainty
  29. jk22

    B Do fractional spins like 4/5 exist?

    In the case of spin 1/2 the state has to be rotated twice 180° to recover the initial one. If we consider a square made of arcs of equators on a sphere. The interior angle on the sphere is chosen to be 108°. Then the sphere is rolled along those arcs on a plane. The square hence draws...
  30. M

    Intuitive explanation of fractional exponents?

    Homework Statement What would have caused humans to come up with fractional exponent notations? Homework EquationsThe Attempt at a Solution I understand that it makes sense to use the exponent notation when we have to multiply the same number a number of times. For example, 10^8 is the short...
  31. B

    MHB Simplify a fractional expression

    Please help with this algebra II question. It needs to be simplified. Thank you.
  32. hilbert2

    A Coupling constants with fractional dimensions

    Most QFT texts, such as Peskin&Schroeder and D. Tong's lecture notes, contain a mention that the renormalizability of an interacting theory requires the coupling constants to have correct dimensions, making scalar fields with ##\phi^5 , \phi^6, \dots## interactions uninteresting. Maybe there are...
  33. S

    Multiplying Algebraic Fractional Exponents

    Homework Statement a3/2a5/4 Homework EquationsThe Attempt at a Solution I'm hoping you can help. My solution to this problem would be: a3/2+5/4=a8/6=a4/3 But the answer in the back of my book is given as a11/4 I'm confused!
  34. D

    Fractional equations w/ binomial denominators

    Homework Statement D+8/D-2 = 9/4 See image, original equation in black. Homework EquationsThe Attempt at a Solution See image. Having a little trouble with this. Ive attempted to solve it two ways. The first was to multiply both sides by ##d-2## which gave me the correct answer of...
  35. M

    MHB Factoring Fractional Expression

    Factor (x^3/8) - (512/x^3). LCD = 8x^3 (x^6 - 8(512))/8x^3 (x^6 - 4096)/8x^3 [(x^3 - 64)(x^3 + 64)]/8x^3 In the numerator, the expression (x^3 - 64) is the difference of cubes, right?
  36. M

    MHB How Do You Factor the Fractional Expression [(a + b)^2]/4 - [a^2b^2]/9?

    Factor [(a + b)^2]/4 - [a^2b^2]/9 Can someone get me started?
  37. M

    LaTeX Efficient Fractional Latex Code for Simplifying Equations

    How can this code be coded by another way? ## \frac {300-270.1}{T-130}## = ## \frac {313.-270.1}{135-130}## And it is also very strange that the right side O.K but left side is not but everything is the same for left and right. #,# \frac {300-270.1}{T-130}## = ## \frac...
  38. K

    I The fractional derivative operator

    I've been thinking about it since yesterday and have noticed this pattern: We have, the first order derivative of a function ##f(x)## is: $$f'(x)=\lim_{h\rightarrow 0}\frac{f(x+h)-f(x)}{h} ...(1)$$ The second order derivative of the same function is: $$f''(x)=\lim_{h\rightarrow...
  39. R

    How Is Fractional Uncertainty Defined When the Measured Value Is Zero?

    <Moderator note: Thread moved from General Physics hence no formatting template shown> The fractional uncertainty is defined as: uncertainty/measured value. So for 2 cm +/- 1 cm we have 50%. For 9 cm +/- 1 cm we have 11.1%. My question is what if the measured value is 0 cm? How is the...
  40. Cjosh

    Pulling fractional exponents out of an expression

    Homework Statement Find critical numbers of the function: F(x)=t^3/4 - 2t^1/4 Derivative I got: F'(x)=3/4 t^-1/4 - 1/2 t^-3/4 Homework EquationsThe Attempt at a Solution I have found the derivative and I understand I must pull out a t in order to find critical numbers, and run across this...
  41. M

    MHB Binomial Expansion - Fractional Powers

    Hello! We know from 'Binomial Expansion' that (1+x)^n=1+nx+\frac{n(n-1)}{2!}x^2+... for \left| x \right|<1 . Why doesn't it work for other values of x? I can't understand this condition. I would be really grateful for clear explanation!
  42. Umar Awan

    Fractional distillation calculations

    Say I have got a super cooled cylinder of half hydrogen and half helium. This cylinder has a pressure of 100,000 Pascal's. At this pressure, hydrogen boils at 20 Kelvin and helium at 4.21 Kelvin. I hope to separate helium by cooling gas down to 4.21 Kelvin but I know that even at the...
  43. D

    MHB Help with a Fractional Equation

    For most of the algebra questions I'm working on, I'm doing okay, with an exception here and there. The good news for those who have helped me, I'm getting a handle on the addition and associative properties and finally learned I needed to subtract on both sides of equation. Feeling better about...
  44. I

    Solution of "polynomial" with integer and fractional powers

    Hello, I have a question regarding "polynomials" that have terms with interger and fractional powers. Homework Statement I want to solve: $$ x+a(x^2-b)^{1/2}+c=0$$ Homework Equations The Attempt at a Solution My approach is to make a change of variable x=f(y) to get a true polynomial (integer...
  45. H

    I Simplifying a fractional factorial with variables

    I am trying to work through a simplication of this factorial with variables: (n/2)!/[(n+2)/2]! I get, 2[n(n-1)]/2[(n+2)(n+1)n(n-1)] cancelling the 2[n(n-1)] leaves me with 1/[(n+2)(n+1)] However, Wolfram Alpha tells me this can be simplified as 2/(n+2) and I don't see that. Thanks
  46. P

    Solving an equation with fractional part function

    Homework Statement If ##\{ x \}## denotes the fractional part of x, then solve: ## \{ x \} + \{ -x \} = x^2 + x -6## It's provided that there are going to be 4 roots of this equation. And two of them will be integers. Homework Equations ## 0 \lt \{ x \} \lt 1~~\text{if}~~x \not\in I## ## \{...
  47. P

    Binomial expansion for fractional power

    Homework Statement So, I'm solving a dipole thing and I have these vectors: |r + d - r'| = (r² + d² - r'²)(1/2) Homework Equations I want to expand this but I have no idea how! I know I may have an infinite power series, but I may expand at the square terms tops... Before I needed to do the...
  48. srinaath

    Why single phase induction motors are used for fractional HP applications

    why single phase induction motor is commonly used for low HP rather than integral HP like 1,2,3HP... i understand that single phase gives low power...but say you have designed such that your motor delivers 10HP for rated voltage and current...why such single phase machines are not common?can...
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