- #1
RedX
- 970
- 3
This is probably a dumb question, but I have a book that claims that if you have a function of the momentum squared, f(p2), that:
[tex]\frac{d}{dp^2}f=\frac{1}{2d}\frac{\partial }{\partial p_\mu}
\frac{\partial }{\partial p^\mu}f[/tex]
where the d in the denominator is the number of spacetime dimensions, so for 4-space the numerical factor would be 1/8.
But this seems to only be true if your function is the identity [itex]f(p^2)=p^2 [/itex], and doesn't hold for all functions f(p^2).
So is the book wrong?
[tex]\frac{d}{dp^2}f=\frac{1}{2d}\frac{\partial }{\partial p_\mu}
\frac{\partial }{\partial p^\mu}f[/tex]
where the d in the denominator is the number of spacetime dimensions, so for 4-space the numerical factor would be 1/8.
But this seems to only be true if your function is the identity [itex]f(p^2)=p^2 [/itex], and doesn't hold for all functions f(p^2).
So is the book wrong?