Finding a maclaurin series for a function with 'e'

In summary, the Maclaurin series for $f(x) = e^{x - 2}$ is $\displaystyle \sum_{n = 0}^{\infty}{\frac{\mathrm{e}^{-2}\,x^n}{n!}}$.
  • #1
tmt1
234
0
I need to find the Maclaurin series for

$$f(x) = e^{x - 2}$$

I know that the maclaurin series for $f(x) = e^x$ is

$$\sum_{n = 0}^{\infty} \frac{x^n}{n!}$$

If I substitute in $x - 2$ for x, I would get

$$\sum_{n = 0}^{\infty} \frac{(x - 2)^n}{n!}$$

However, this is wrong, according to the text. How can I fix this?
 
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  • #2
tmt said:
I need to find the Maclaurin series for

$$f(x) = e^{x - 2}$$

I know that the maclaurin series for $f(x) = e^x$ is

$$\sum_{n = 0}^{\infty} \frac{x^n}{n!}$$

If I substitute in $x - 2$ for x, I would get

$$\sum_{n = 0}^{\infty} \frac{(x - 2)^n}{n!}$$

However, this is wrong, according to the text. How can I fix this?

The reason it's considered wrong in the text is because you have a Taylor series centred around x = 2, while a MacLaurin series is strictly only centred around x = 0.

For this one $\displaystyle \begin{align*} \mathrm{e}^{x - 2} = \mathrm{e}^{-2}\,\mathrm{e}^x = \mathrm{e}^{-2}\,\sum_{n = 0}^{\infty}{ \frac{x^n}{n!} } = \sum_{n = 0}^{\infty}{\frac{\mathrm{e}^{-2}\,x^n}{n!}} \end{align*}$.
 

1. How do you find the Maclaurin series for a function with e?

To find the Maclaurin series for a function with e, you can use the formula: f(x) = e^x = Σ (n=0 to ∞) [f^n(0) / n!] * x^n. This formula represents the Taylor series expansion for the function e^x centered at x=0, which is also known as the Maclaurin series.

2. What is the purpose of finding the Maclaurin series for a function with e?

The purpose of finding the Maclaurin series for a function with e is to be able to represent the function as a sum of infinitely many terms, each with a different power of x. This can be helpful in simplifying calculations and approximating the value of the function for different values of x.

3. Is the Maclaurin series for a function with e always accurate?

The Maclaurin series for a function with e is only accurate for a specific range of values of x, depending on the function. The more terms that are included in the series, the more accurate the approximation will be. However, for some functions, the Maclaurin series may not converge for all values of x, so it is important to check the convergence of the series before using it.

4. Can the Maclaurin series for a function with e be used to find the value of the function at any point?

Yes, the Maclaurin series can be used to find the value of the function at any point within the convergence range. However, it is important to note that the series is an approximation and may not give an exact value.

5. How does the Maclaurin series for a function with e differ from the Taylor series?

The Maclaurin series is a special case of the Taylor series, where the expansion is centered at x=0. The Taylor series, on the other hand, can be centered at any point within the convergence range. Additionally, the coefficients in the Maclaurin series are calculated using the derivatives of the function at x=0, while in the Taylor series, the coefficients are calculated using the derivatives at the chosen center point.

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