Taylor Series for f(x) = (1+x)^m

Grew Gore

Homework Statement


i) What is the Taylor Series for f(x) = (1+x)^m about x=0 where m is a real number?
ii) Why does this binomial series terminate when m is a non-negative integer? A
iii) Can the result to (i) be used to find the first four non-zero terms of the series for (1+x)^(-1/2)


Homework Equations

The Attempt at a Solution


I started getting: 1 + mx + 1/2(m-1)mx^2 +1/6(m-2)(m-1)mx^3 +... but am unsure if this is right and how to go on from here.
 
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That looks correct for (i) although they may prefer you to use general summation notation rather than '+...'
Now do (ii). Hint: Which, if any, of the terms in the expansion you wrote as answer to (i) will be zero if m is a positive integer?
 
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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