A complicated taylor polynomial

In summary, there is a clever trick for finding the Taylor polynomial of a composition of two functions, both of which can be expressed as Taylor polynomials themselves. This method involves calculating the derivative and evaluating it, and there is a specific formula for determining the coefficients of the series.
  • #1
IMDerek
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Is there any nice trick for finding the Taylor polynomial of a composition of 2 functions, both of which can be expressed as taylor polynomials themselves? For example, finding the taylor polynomial for [tex]e^{\cos x}[/tex]. Thanks.
 
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  • #2
Well, for example, near [itex]\pi/2[/tex]

[tex]e^{\cos x}=1+\cos x+ \frac{cos^2 x}{2!}+\frac{\cos^3 x}{3!}+...[/tex]

and

[tex]\cos x=-\frac{(x-\pi/2)^2}{2!}+\frac{(x-\pi/2)^4}{4!}-...[/tex]

now, the hard part is to compose it, so maybe it's easier to just calculate the derivative and evaluate, depends on what are you looking for.
 
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1. What is a Taylor polynomial?

A Taylor polynomial is a mathematical expression used to approximate a more complex function. It is created by taking derivatives of the function at a specific point and evaluating them to find the coefficients of the polynomial. The higher the degree of the polynomial, the more accurate the approximation will be.

2. How is a Taylor polynomial different from a regular polynomial?

A Taylor polynomial takes into account the derivatives of a function at a specific point, while a regular polynomial does not. This means that a Taylor polynomial is a more precise approximation of a function, especially when the function is non-linear or has a complex shape.

3. What is the purpose of using a Taylor polynomial?

The main purpose of using a Taylor polynomial is to approximate a more complex function with a simpler one. This allows for easier mathematical calculations and analysis. Taylor polynomials are also used in fields such as physics and engineering to model and predict real-world phenomena.

4. How do you determine the degree of a Taylor polynomial?

The degree of a Taylor polynomial is determined by the number of derivatives used in its creation. For example, a Taylor polynomial with one derivative would be a first-degree polynomial, while a polynomial with four derivatives would be a fourth-degree polynomial.

5. What is the remainder term in a Taylor polynomial?

The remainder term in a Taylor polynomial is the difference between the actual value of the function and the value of the polynomial at a given point. It represents the error or inaccuracy of the polynomial's approximation and can be used to determine the accuracy of the polynomial for a specific function.

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