Integral x/(1-x) via power series?

In summary, the conversation discusses solving the integral ∫x/(1-x) using a power series and whether a specific solution using a summation is correct and preferable to other methods.
  • #1
fahraynk
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So, ∫x/(1-x)... can I solve this as a power series

∫(x*Σ x^n) = ∫(Σ x^(n+1))= (1/(n+2)*Σ x^(n+2))?

Is this correct? I know there is other ways to do it... But should this be correct on a test? This solution is more fun..
 
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  • #2
fahraynk said:
So, ∫x/(1-x)... can I solve this as a power series

∫(x*Σ x^n) = ∫(Σ x^(n+1))= (1/(n+2)*Σ x^(n+2))?

Is this correct? I know there is other ways to do it... But should this be correct on a test? This solution is more fun..

More fun than what? More fun than the exact expression? Is a solution of limited applicability (i.e., is correct only for limited values of x) preferable to one that applies to all x ≠ 1?
 
Last edited:
  • #3
Ray Vickson said:
More fun than what? More fun than the exact expression? Is a solution of limited applicability (i.e., is correct only for limited values of x) preferable to one that applies to all x ≠ 1?
Ha. Good point.
 

Related to Integral x/(1-x) via power series?

1. What is the general formula for the power series of integral x/(1-x)?

The general formula for the power series of integral x/(1-x) is ∑n=0 xn+1 = x + x2 + x3 + ... + xn+1 + ...

2. How do you find the coefficients of the power series for integral x/(1-x)?

The coefficients of the power series for integral x/(1-x) can be found using the formula cn = ∫01 xn dx, where cn is the coefficient of xn.

3. What is the interval of convergence for the power series of integral x/(1-x)?

The interval of convergence for the power series of integral x/(1-x) is -1 < x < 1.

4. How can the power series for integral x/(1-x) be used to evaluate the integral?

The power series for integral x/(1-x) can be used to evaluate the integral by substituting x with the variable of integration and summing the resulting series.

5. Can the power series for integral x/(1-x) be used to approximate the integral for values outside the interval of convergence?

No, the power series for integral x/(1-x) can only be used to approximate the integral for values within the interval of convergence, which is -1 < x < 1.

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