Power Series Representation of e^(sin(x))

In summary, the power series representation of f(x) = e^(sin(x)) is given by \sum_{r=0}^{\infty}\frac{1}{r!}(\sum_{t=0}^{\infty} \ \frac{(-1)^r (sin(x))^t}{(2t+1)!}).
  • #1
mouser
9
0

Homework Statement



Find the power series representation of the following:

f(x) = e^(sin(x))

Homework Equations



I know this to be true:

e^x = (Inf Sum, n=0) (x^n/n!)

The Attempt at a Solution



So, in substituting sin(x) for x, I get:

e^(sin(x)) = 1 + sin(x)/1 + sin(x)/2 + sin(x)/6 + ...

or

e^(sin(x)) = (Inf Sum, n=0) ((sin(x))^n/n!)

Not sure where I'm going wrong here, so a nudge in the right direction would be greatly appreciated. Thanks in advance!
 
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  • #2
Does anyone have any advice here? I have an exam tomorrow, for which I am almost fully prepared. With my luck though, this problem will be on the exam and I'll be screwed!

Any help would be much appreciated!
 
  • #3
Also, by (Inf Sum, n=0), I meant [tex]\sum[/tex]

Thanks
 
  • #4
I think everybody knows what you mean. You presented the problem pretty clearly. But I don't know how to express the nth term of your series in any nice closed form. If nobody answered they probably don't either. It's pretty easy to find the first few terms by expanding sin(x) as a series. But I don't know the general term.
 
  • #5
In short, we have to simplify this:

[tex]\sum_{r=0}^{\infty}\frac{1}{r!}(\sum_{t=0}^{\infty} \ \frac{(-1)^tx^{2t+1}}{(2t+1)!})^r[/tex]

That looks pretty horrendous to begin with.
 
  • #6
Maybe that IS the answer...
 
  • #7
Except, incorporate the 'r' as t's
 

1. What is a power series representation?

A power series representation is a mathematical expression that represents a function as an infinite sum of powers of a variable. It is a useful tool for representing and approximating complex functions.

2. How is e^(sin(x)) represented as a power series?

The power series representation of e^(sin(x)) is given by the infinite sum: e^(sin(x)) = 1 + sin(x) + (sin(x))^2/2! + (sin(x))^3/3! + ... + (sin(x))^n/n! + ...

3. Why is a power series representation useful for e^(sin(x))?

A power series representation allows us to approximate the value of e^(sin(x)) for any value of x, as long as we have enough terms in the series. This can be useful in solving problems in physics, engineering, and other fields.

4. What is the convergence of the power series representation of e^(sin(x))?

The power series representation of e^(sin(x)) converges for all values of x. This means that as we add more terms to the series, the approximation of e^(sin(x)) becomes closer to the actual value.

5. How accurate is the power series representation of e^(sin(x))?

The accuracy of the power series representation of e^(sin(x)) depends on the number of terms used. The more terms we include, the more accurate the approximation will be. However, since it is an infinite series, it can never be exact.

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