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Commutators for functions of operators (momentum/position)

  • Thread starter Ratpigeon
  • Start date
  • #1
56
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Homework Statement



show that [x,f(p_x)] = i [itex]\hbar[/itex] d/d(p_x) f(p_x)

Homework Equations



x is the position operator in the x direction, p_x is the momentum operator; i [itex]\hbar[/itex]
d/dx
[x, p_x]=xp-px

The Attempt at a Solution


I'm stuck. maybe chain rule for d/dx and d/d(p_x)...? But I don't see how I'd do it...
 

Answers and Replies

  • #2
56
0
Never mind - I had to reqresent it as a power series, and then it was easier
 

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