Taylor approximation Definition and 26 Threads

  1. Z

    I Spivak, Ch. 20: Understanding a step in the proof of lemma

    In Chapter 20 of Spivak's Calculus is the lemma shown below (used afterward to prove Taylor's Theorem). My question is about a step in the proof of this lemma. Here is the proof as it appears in the book My question is: how do we know that ##(R')^{n+1}## is defined in ##(2)##? Let me try to...
  2. M

    State space controllers - find equations from differentials

    Summary:: This is similar to the examples of electrical circuit state space analysis, I have been trying to find the state space equations from the following non linear first order differentials but I keep getting stuck. Any help? A) Started off from non linear equations: $$y' =...
  3. B

    4th order Taylor approximation

    So I just followed Taylor's formula and got the four derivatives at p = 0 ##f^{(0)}(p) = (1 + \frac {p^2} {m^2c^2})^{\frac 1 2} ## ##f^{(0)}(0) = 1 ## ## f^{(1)}(p) = \frac {p} {m^2c^2}(1 + \frac {p^2} {m^2c^2})^{\frac {-1} 2} ## ## f^{(1)}(0) = 0 ## ## f^{(2)}(p) = \frac {1} {m^2c^2}(1 +...
  4. Jason Bennett

    (Physicist version of) Taylor expansions

    3) Taylor expansion question in the context of Lie algebra elements: Consider some n-dimensional Lie group whose elements depend on a set of parameters \alpha =(\alpha_1 ... \alpha_n) such that g(0) = e with e as the identity, and that had a d-dimensional representation D(\alpha)=D(g( \alpha)...
  5. Adgorn

    Limit of the remainder of Taylor polynomial of composite functions

    Since $$\lim_{x \rightarrow 0} \frac {R_{n,0,f}(x)} {x^n}=0,$$ ##P_{n,0,g}(x)## contains only terms of degree ##\geq 1## and ##R_{n,0,g}## approaches ##0## as quickly as ##x^n##, I can most likely prove this using ##\epsilon - \delta## arguments, but that seems overly complicated. I also can't...
  6. S

    Lagrange error bound inequality for Taylor series of arctan(x)

    The error ##e_{n}(y)## for ##\frac{1}{1-y}## is given by ##\frac{1}{(1-c)^{n+2}}y^{n+1}##. It follows that ##\frac{1}{1+y^2}=t_n(-y^2)+e_n(-y^2)## where ##t_n(y)## is the Taylor polynomial of ##\frac{1}{1-y}##. Taking the definite integral from 0 to ##x## on both sides yields that...
  7. U

    A Taylor expansion for a nonlinear system and Picard Iterations

    Hello guys I struggle since yesterday with the following problem I am reading the book "Elements of applied bifurcation theory" by Kuznetsov . At one point he has the following Taylor expansion of a nonlinear system with respect to x=0 where ##x\in \mathbb(R)^n## $$\dot{x} = f(x) = \Lambda x +...
  8. D

    Derivative of expanded function wrt expanded variable?

    Homework Statement If I have the following expansion f(r,t) \approx g(r) + \varepsilon \delta g(r,t) + O(\varepsilon^2) This means for other function U(f(r,t)) U(f(r,t)) = U( g(r) + \varepsilon \delta g(r,t)) \approx U(g) + \varepsilon \delta g \dfrac{dU}{dg} + O(\varepsilon^2) Then up to...
  9. Jozefina Gramatikova

    By calculating a Taylor approximation, determine K

    Homework Statement Homework Equations [/B]The Attempt at a Solution Can somebody explain to me how did we find the function in red? Thanks
  10. A

    Solving Schrodinger's Equation with a weak Imaginary Potential

    Homework Statement A particle of energy E moves in one dimension in a constant imaginary potential -iV where V << E. a) Find the particle's wavefunction \Psi(x,t) approximating to leading non-vanishing order in the small quantity \frac{V}{E} << 1. b) Calculate the probability current density...
  11. Poetria

    Approximating square root of 2 (Taylor remainder)

    Homework Statement [/B] Use the Taylor remainder theorem to give an expression of ##\sqrt 2 - P_3(1)## P_3(x) - the degree 3 Taylor polynomial ##\sqrt {1+x}## in terms of c, where c is some number between 0 and 1 Find the maximum over the interval [0, 1] of the absolute value of the...
  12. Adgorn

    I Understanding the Taylor Expansion of a Translated Function

    I recently found out the rule regarding the Taylor expansion of a translated function: ##f(x+h)=f(x)+f′(x)⋅h+\frac 1 2 h^ 2 \cdot f′′(x)+⋯+\frac 1 {n!}h^n \cdot f^n(x)+...## But why exactly is this the case? The normal Taylor expansion tells us that ##f(x)=f(a)+f'(a)(x-a)+\frac 1...
  13. S

    Approximating a spring constant for an air leg

    Hi all, In short: For an air leg or air spring, there is a method using a Taylor approximation to find the spring constant for very small displacements, but I can't seem to figure out how it works. I've learned that air legs don't follow Hooke's law very much at all, except for when the...
  14. tanvi nautiyal

    I Second order Taylor approximation

    Hello, Can someone explain this to me? In the above case ct=yt-gt I tried to solve it as a three variable taylor approximation but got a few extra terms that weren't included in the above. So I am a little confused now. I only need to understand how the first line was derived because I get...
  15. E

    Calculus Taylor Approximation Proof

    1. The question is. Show that if |nx| <1, the following is exact up to (and including) the x^2 order. The hint giving says to use the Taylor Expansion for both sides of the equation2. (1+x)^n = e^n(x-(1/2)x^2) ; the n(x-(1/2)x^2) is all an exponent3. My first attempt was to take the taylor...
  16. Nugso

    Taylor Approximation: Show ∫f'(x)dx/f(x)=ln|f(x)|+C

    Homework Statement Show that ∫f'(x)dx/f(x) = ln|(f(x)|+C where f(x) is a differential function. Homework Equations First order Taylor approximation? f(x)=f(a)+f'(a)(x-a) The Attempt at a Solution Well, I'm not really sure how to approach the question. It's my Numerical...
  17. A

    Taylor Approximation: Error Calculation Tool?

    Often you use taylor series to approximate differential equations for easier solving. An example is the small angle approximation to the pendulum. My question is: Is there mathematical tool for calculating the error you make as time goes with such an approximation? Because I could Imagine it...
  18. I

    Taylor approximation of the Doppler Law for slow-moving emitters

    The relationship linking the emitted frequency Fe and the received frequency Fr is the Doppler Law: F_r = \sqrt \frac{1-\frac{v}{c}}{1-\frac{v}{c}} F_e The Taylor series for the function \sqrt\frac{1+x}{1-x} near x = 0 is 1+x+\frac{x^2}{2}+\frac{x^3}{3}+... On Earth, most objects travel...
  19. E

    Taylor Approximation (I think) on Transmission Coefficient

    Homework Statement I have this equation: T=(1+\frac{U_{0}^{2}}{4E(U_{0}-E)}sinh^{2}(2 \alpha L))^{-1} Where α is given by: \alpha = \sqrt{ \frac{2m(U_{0}-E)}{\hbar^{2}}} I have to show that in the limit αL>>1 my equation is approximately given by...
  20. R

    How to Calculate Taylor Approximations for Given Function and Parameters?

    Homework Statement find the 2nd, 3rd, and 6th degree taylor approximation of: f(x) = 10(x/2 -0.25)5 + (x-0.5)3 + 9(x-0.75)2-8(x-0.25)-1 for h = 0.1 to h = 1, with \Deltah = 0.05 and where xo=0; and x = h Homework Equations N.A The Attempt at a Solution I just need to...
  21. M

    Help with understanding taylor approximation

    Homework Statement I'm reading about fluid mechanics and in one of the examples they have approximated the velocity field. The field is two dimensional u = (u,v) I have never seen this before so cold someone tell me what it is called so I can look it up? The notes I am reading are hand...
  22. P

    Taylor approximation (probability)

    I have the following problem: Assume g is a (smooth enough) function, X a random variable and \varepsilon^h a sequence of random variables, whose moments converge to 0 as h goes to zero. I would then like to prove that \mathbb{E}\left|g(X+\varepsilon^h)-g(X)\right| converges to zero as well...
  23. M

    Very quick Taylor Approximation Question

    Homework Statement Let f(x) = sin x a) find p_6 (taylor polynomial 6th degree) for f at x = 0 b) How accurate is this on the interval [-1,1] Homework Equations The Attempt at a Solution I got p_6 = x + (x^3)/6 + (x^5)/120, which was correct as per the solution manual. My...
  24. E

    Taylor Approximation Proof for P(r) using Series Expansion

    [SOLVED] Taylor approximation Homework Statement I have an exact funktion given as: P(r)=1-e^{\frac{-2r}{a}}(1+\frac{2r}{a}+\frac{2r^2}{a^2}) I need to prove, by making a tayler series expansion, that: P(r)\approx \frac{3r^3}{4a^4} When r \prec \prec a The Attempt at a Solution...
  25. S

    Taylor Approximation Help - Find n Given x, a, ErrorBound

    Hi, I'm having trouble doing my work where I have to find the Taylor Approximation of function. My real work is the program this thing when the function, x, a, and ErrorBound is given. I don't knwo what to do with the ErrorBound to get n, where n is the number of terms. do i make any sense...
  26. L

    Confused about taylor approximation

    I am a bit confused about taylor approximation. Taylor around x_0 yields f(x) = f(x_0) + f'(x_0)(x-x_0) + O(x^2) which is the tangent of f in x_0, where f'(x) = f'(x_0) + f''(x_0)(x-x_0) + O(x^2) which adds up to f(x) &=& f(x_0) + (f'(x_0) + f''(x_0)(x-x_0) +...
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