Taylor series for the following

In summary, the question asks for the Taylor or MacLauren series centered around a given value for the function Ln z, and to determine the radius of convergence. The formula for Log z is ln|z| + i(Arg z), but the process for finding the radius of convergence is not remembered from Calc 2. It is possible to simplify a series in terms of (2z + i)^2n to be in terms of 2^(2n)(z + i/2)^2n, and the radius can be found by taking the square root of the radius of the original series. If the radius is less than 1/2, it can be concluded that the series about the point z + i/2 does
  • #1
TheFerruccio
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I have a couple of general questions, combined with this one specific question

Homework Statement



Find the Taylor or MacLauren series centered about the given value for the following function, determine the radius of convergence

Homework Equations



[tex]\mathrm{Ln}\ z[/tex], 2

The Attempt at a Solution



I know that
[tex]\mathrm{Log}\ z = \ln{|z|} + i\left(\mathrm{Arg}\ z\right)[/tex]

But, I don't know where to go from here, nor do I know how to find a relevant pattern for find the radius of convergence. It might just be an issue of not remembering this from Calc 2.

Also, from earlier questions, if have some series that's in terms of something like [tex]\left(2z+i\right)^{2n}[/tex] Can I just simplify it to be in terms of [tex]2^{2n} \left(z+\frac{i}{2}\right)^{2n}[/tex], then have the radius be the square root of whatever the radius would be if it was in terms of [tex]\left(z+\frac{i}{2}\right)^{n}[/tex]? Then, if the radius is less than 1/2, then it can be determined that the series about the point [tex]z+\frac{i}{2}[/tex] does not converge?
 
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  • #2
I think, all I have to do is just treat the principle natural log as a regular natural log, not splitting it up into anything the definition calls for, then just evaluate it that way, with the radius of convergence being from the point of evaluation to where the natural log ceases to exist. In this case, by observation, R would be 2, but I'll verify it with a Taylor series.
 

FAQ: Taylor series for the following

What is a Taylor series?

A Taylor series is a representation of a function as an infinite sum of terms, where each term is a polynomial approximation of the function at a specific point. It is used to approximate functions that are difficult to evaluate directly.

What is the formula for a Taylor series?

The formula for a Taylor series is: f(x) = f(a) + f'(a)(x-a) + (f''(a)/2!)(x-a)^2 + (f'''(a)/3!)(x-a)^3 + ... where f(x) is the function, a is the point of approximation, and f'(a), f''(a), f'''(a), etc. are the derivatives of the function at a.

Why is the Taylor series important?

The Taylor series is important because it allows us to approximate complex functions with simpler polynomial functions. This makes it easier to perform calculations and solve problems in mathematics and physics.

How do you find the coefficients of a Taylor series?

The coefficients of a Taylor series can be found by taking the derivatives of the function at the point of approximation and plugging them into the formula for the Taylor series. Alternatively, they can also be found by using the Taylor series expansion formula.

What is the difference between a Taylor series and a Maclaurin series?

A Taylor series is a representation of a function at any point, while a Maclaurin series is a special case of a Taylor series where the point of approximation is a = 0. This means that the Maclaurin series only uses the derivatives of the function evaluated at x = 0.

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