The error of a Taylor polynomial (relativistic kinetic energy)
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I have been trying to utilize the formula:
I simply cannot figure out how to determine the error when using
Instead of:
I have made a Taylor polynomial around 0 of grade 4, and I cannot find the deviation when using the Taylor polynomial instead of the original function.
The Taylor polynomial is:
And it was made of the Lorentz factor:
real-analysis taylor-expansion
$endgroup$
add a comment |
$begingroup$
I have been trying to utilize the formula:
I simply cannot figure out how to determine the error when using
Instead of:
I have made a Taylor polynomial around 0 of grade 4, and I cannot find the deviation when using the Taylor polynomial instead of the original function.
The Taylor polynomial is:
And it was made of the Lorentz factor:
real-analysis taylor-expansion
$endgroup$
$begingroup$
Did you have a look at Taylor-Lagrange formula ?
$endgroup$
– Damien
Dec 16 '18 at 8:23
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Yes I have, but I cannot figure out how to implement it. Every example of using it that I can find, uses the the natural exponential function or a trigonometric function, and their bound is easy to figure out.
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– Nikolai
Dec 16 '18 at 10:58
$begingroup$
You can get a bound on the error with Taylor-Lagrange as soon as you can calculate the Taylor series. What is blocking you ?
$endgroup$
– Damien
Dec 16 '18 at 12:28
$begingroup$
Well i have made the taylor series, but don't understand how i get the bound
$endgroup$
– Nikolai
Dec 16 '18 at 15:58
add a comment |
$begingroup$
I have been trying to utilize the formula:
I simply cannot figure out how to determine the error when using
Instead of:
I have made a Taylor polynomial around 0 of grade 4, and I cannot find the deviation when using the Taylor polynomial instead of the original function.
The Taylor polynomial is:
And it was made of the Lorentz factor:
real-analysis taylor-expansion
$endgroup$
I have been trying to utilize the formula:
I simply cannot figure out how to determine the error when using
Instead of:
I have made a Taylor polynomial around 0 of grade 4, and I cannot find the deviation when using the Taylor polynomial instead of the original function.
The Taylor polynomial is:
And it was made of the Lorentz factor:
real-analysis taylor-expansion
real-analysis taylor-expansion
edited Dec 16 '18 at 6:07
Moo
5,62131020
5,62131020
asked Dec 16 '18 at 1:22
Nikolai Nikolai
205
205
$begingroup$
Did you have a look at Taylor-Lagrange formula ?
$endgroup$
– Damien
Dec 16 '18 at 8:23
$begingroup$
Yes I have, but I cannot figure out how to implement it. Every example of using it that I can find, uses the the natural exponential function or a trigonometric function, and their bound is easy to figure out.
$endgroup$
– Nikolai
Dec 16 '18 at 10:58
$begingroup$
You can get a bound on the error with Taylor-Lagrange as soon as you can calculate the Taylor series. What is blocking you ?
$endgroup$
– Damien
Dec 16 '18 at 12:28
$begingroup$
Well i have made the taylor series, but don't understand how i get the bound
$endgroup$
– Nikolai
Dec 16 '18 at 15:58
add a comment |
$begingroup$
Did you have a look at Taylor-Lagrange formula ?
$endgroup$
– Damien
Dec 16 '18 at 8:23
$begingroup$
Yes I have, but I cannot figure out how to implement it. Every example of using it that I can find, uses the the natural exponential function or a trigonometric function, and their bound is easy to figure out.
$endgroup$
– Nikolai
Dec 16 '18 at 10:58
$begingroup$
You can get a bound on the error with Taylor-Lagrange as soon as you can calculate the Taylor series. What is blocking you ?
$endgroup$
– Damien
Dec 16 '18 at 12:28
$begingroup$
Well i have made the taylor series, but don't understand how i get the bound
$endgroup$
– Nikolai
Dec 16 '18 at 15:58
$begingroup$
Did you have a look at Taylor-Lagrange formula ?
$endgroup$
– Damien
Dec 16 '18 at 8:23
$begingroup$
Did you have a look at Taylor-Lagrange formula ?
$endgroup$
– Damien
Dec 16 '18 at 8:23
$begingroup$
Yes I have, but I cannot figure out how to implement it. Every example of using it that I can find, uses the the natural exponential function or a trigonometric function, and their bound is easy to figure out.
$endgroup$
– Nikolai
Dec 16 '18 at 10:58
$begingroup$
Yes I have, but I cannot figure out how to implement it. Every example of using it that I can find, uses the the natural exponential function or a trigonometric function, and their bound is easy to figure out.
$endgroup$
– Nikolai
Dec 16 '18 at 10:58
$begingroup$
You can get a bound on the error with Taylor-Lagrange as soon as you can calculate the Taylor series. What is blocking you ?
$endgroup$
– Damien
Dec 16 '18 at 12:28
$begingroup$
You can get a bound on the error with Taylor-Lagrange as soon as you can calculate the Taylor series. What is blocking you ?
$endgroup$
– Damien
Dec 16 '18 at 12:28
$begingroup$
Well i have made the taylor series, but don't understand how i get the bound
$endgroup$
– Nikolai
Dec 16 '18 at 15:58
$begingroup$
Well i have made the taylor series, but don't understand how i get the bound
$endgroup$
– Nikolai
Dec 16 '18 at 15:58
add a comment |
1 Answer
1
active
oldest
votes
$begingroup$
Let us call $f(t)$ the function
$$f(t) = frac{1}{sqrt{1-t}} $$
The $k^{th}$ derivative function of $f()$ is equal to
$$f^{k}(t) = frac{prod_{i=1}^k{(2i-1)}}{2^k} (1-t)^{-frac{2k+1}{2}} $$
This last relation can for example be demonstrated by recurrence.
According to Taylor-Lagrange formula, there exists $xi$ between $0$ and $t$ such that
$$f(t) = 1 + frac{t}{2} + frac{3}{8}t^2 + frac{5}{16}(1-xi)^{-7/2},t^3 = 1 + frac{t}{2} + frac{3}{8}t^2 + R(t)$$
It follows
$$0 < R(t) < frac{5}{16}(1-t)^{-7/2},t^3 $$
Now, one just have to replace $t$ :
$$t = x^2 = left(frac{v}{c}right)^2$$
$endgroup$
add a comment |
Your Answer
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
Let us call $f(t)$ the function
$$f(t) = frac{1}{sqrt{1-t}} $$
The $k^{th}$ derivative function of $f()$ is equal to
$$f^{k}(t) = frac{prod_{i=1}^k{(2i-1)}}{2^k} (1-t)^{-frac{2k+1}{2}} $$
This last relation can for example be demonstrated by recurrence.
According to Taylor-Lagrange formula, there exists $xi$ between $0$ and $t$ such that
$$f(t) = 1 + frac{t}{2} + frac{3}{8}t^2 + frac{5}{16}(1-xi)^{-7/2},t^3 = 1 + frac{t}{2} + frac{3}{8}t^2 + R(t)$$
It follows
$$0 < R(t) < frac{5}{16}(1-t)^{-7/2},t^3 $$
Now, one just have to replace $t$ :
$$t = x^2 = left(frac{v}{c}right)^2$$
$endgroup$
add a comment |
$begingroup$
Let us call $f(t)$ the function
$$f(t) = frac{1}{sqrt{1-t}} $$
The $k^{th}$ derivative function of $f()$ is equal to
$$f^{k}(t) = frac{prod_{i=1}^k{(2i-1)}}{2^k} (1-t)^{-frac{2k+1}{2}} $$
This last relation can for example be demonstrated by recurrence.
According to Taylor-Lagrange formula, there exists $xi$ between $0$ and $t$ such that
$$f(t) = 1 + frac{t}{2} + frac{3}{8}t^2 + frac{5}{16}(1-xi)^{-7/2},t^3 = 1 + frac{t}{2} + frac{3}{8}t^2 + R(t)$$
It follows
$$0 < R(t) < frac{5}{16}(1-t)^{-7/2},t^3 $$
Now, one just have to replace $t$ :
$$t = x^2 = left(frac{v}{c}right)^2$$
$endgroup$
add a comment |
$begingroup$
Let us call $f(t)$ the function
$$f(t) = frac{1}{sqrt{1-t}} $$
The $k^{th}$ derivative function of $f()$ is equal to
$$f^{k}(t) = frac{prod_{i=1}^k{(2i-1)}}{2^k} (1-t)^{-frac{2k+1}{2}} $$
This last relation can for example be demonstrated by recurrence.
According to Taylor-Lagrange formula, there exists $xi$ between $0$ and $t$ such that
$$f(t) = 1 + frac{t}{2} + frac{3}{8}t^2 + frac{5}{16}(1-xi)^{-7/2},t^3 = 1 + frac{t}{2} + frac{3}{8}t^2 + R(t)$$
It follows
$$0 < R(t) < frac{5}{16}(1-t)^{-7/2},t^3 $$
Now, one just have to replace $t$ :
$$t = x^2 = left(frac{v}{c}right)^2$$
$endgroup$
Let us call $f(t)$ the function
$$f(t) = frac{1}{sqrt{1-t}} $$
The $k^{th}$ derivative function of $f()$ is equal to
$$f^{k}(t) = frac{prod_{i=1}^k{(2i-1)}}{2^k} (1-t)^{-frac{2k+1}{2}} $$
This last relation can for example be demonstrated by recurrence.
According to Taylor-Lagrange formula, there exists $xi$ between $0$ and $t$ such that
$$f(t) = 1 + frac{t}{2} + frac{3}{8}t^2 + frac{5}{16}(1-xi)^{-7/2},t^3 = 1 + frac{t}{2} + frac{3}{8}t^2 + R(t)$$
It follows
$$0 < R(t) < frac{5}{16}(1-t)^{-7/2},t^3 $$
Now, one just have to replace $t$ :
$$t = x^2 = left(frac{v}{c}right)^2$$
edited Dec 16 '18 at 22:00
answered Dec 16 '18 at 21:52
DamienDamien
59714
59714
add a comment |
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$begingroup$
Did you have a look at Taylor-Lagrange formula ?
$endgroup$
– Damien
Dec 16 '18 at 8:23
$begingroup$
Yes I have, but I cannot figure out how to implement it. Every example of using it that I can find, uses the the natural exponential function or a trigonometric function, and their bound is easy to figure out.
$endgroup$
– Nikolai
Dec 16 '18 at 10:58
$begingroup$
You can get a bound on the error with Taylor-Lagrange as soon as you can calculate the Taylor series. What is blocking you ?
$endgroup$
– Damien
Dec 16 '18 at 12:28
$begingroup$
Well i have made the taylor series, but don't understand how i get the bound
$endgroup$
– Nikolai
Dec 16 '18 at 15:58