Why is the correction important?

Soccerdude
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Homework Statement



Find the Taylor series of f(x) = x2ln(1+2x2) centered at c = 0.


Homework Equations



Taylor Series of f(x) = ln(1+x) is Ʃ from n=1 to ∞ of (-1)n-1xn/n

The Attempt at a Solution



I have worked the problem to

(-1)n4nx2n/n

I am not sure where to go from here

Thank You!
 
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Soccerdude said:

Homework Statement



Find the Taylor series of f(x) = x2ln(1+2x2) centered at c = 0.


Homework Equations



Taylor Series of f(x) = ln(1+x) is Ʃ from n=1 to ∞ of (-1)n-1xn/n

The Attempt at a Solution



I have worked the problem to

(-1)n4nx2n/n

I am not sure where to go from here

Thank You!
Well, you seem to have the right idea for the Taylor series of ln(1+2x2). It's not quite right.

\displaystyle \left(2x^2\right)^n=2^nx^{2n}\ .

When you make the correction for that, then just multiply by x2 , to get the Taylor series for x2ln(1+2x2).
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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