 #1
MathematicalPhysicist
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 TL;DR Summary

Some algebraic manipulation, which I think there's a misprint in the book.
Please let me know what do you think?
Attached is a pic of the page in the book:
My problem is with equation (11.34) specifically with the term ##\frac{6M^3}{L^2}y## I get ##L^4## instead of ##L^2##.
Here are my calculations (I also checked it with maple's expand command):
$$\frac{E^21}{L^2}+\frac{2M^2}{L^4}+\frac{2M}{L^2}y[y^2+\frac{2yM}{L^2}+\frac{M^2}{L^4}]+$$
$$+2M[y^3+\frac{M^3}{L^6}+3y^2\frac{M}{L^2}+3y\frac{M^2}{L^4}]$$
so if we neglect the term ##2My^3##, we should be getting as I wrote.
I don't see where did I make a mistake?
Can you spot it?
Thanks!
My problem is with equation (11.34) specifically with the term ##\frac{6M^3}{L^2}y## I get ##L^4## instead of ##L^2##.
Here are my calculations (I also checked it with maple's expand command):
$$\frac{E^21}{L^2}+\frac{2M^2}{L^4}+\frac{2M}{L^2}y[y^2+\frac{2yM}{L^2}+\frac{M^2}{L^4}]+$$
$$+2M[y^3+\frac{M^3}{L^6}+3y^2\frac{M}{L^2}+3y\frac{M^2}{L^4}]$$
so if we neglect the term ##2My^3##, we should be getting as I wrote.
I don't see where did I make a mistake?
Can you spot it?
Thanks!