Thank you Alan,
How did you do the initial expansion? What kind of an expansion is that?
Thanks Alan but worry too much, I don't understand expansions much. :(
I only know the binomial expansion.
I just wondered :/
Thanks Alan,
I can follow most of that but you lost me at O(x2) and what happened to all the other powers of x?
Only answer is you feel enthused because this stuff is really over my head. I couldn't reproduce it. :(
Rather than writing all the other terms involving x2, x3 etc. I've written O(x2), meaning terms of order x2 and smaller ("smaller" because we are going to make x go to 0, so x4, x3 etc. are going to be smaller than x2). The important thing is that all these other terms will be multiples of xn, where n>1, so that when they are divided by x they are still mutiples of powers of x and hence vanish in the limit as x tends to 0.
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