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Homework Statement
Using [x,eiap]=-ħaeiap show that xneiap = eiap(x-ħa)n
Homework Equations
[x,eiap]=-ħaeiap
From which it follows that,
xeiap = eiap(x-ħa)
The Attempt at a Solution
[xn,eiap] = [xxn-1,eiap]
= [x,eiap]xn-1 + x[xn-1,eiap]
= -ħaeiapxn-1 + x(xn-1eiap-eiapxn-1)
= -ħaeiapxn-1 + xneiap - eiap(x-ħa)xn-1
Expanding the original commutator on the LHS and moving the second term to the RHS gives,
xneiap = -ħaeiapxn-1 + xneiap - eiap(x-ħa)xn-1 + eiapxn
= -ħaeiapxn-1 + xneiap + ħaeiapxn-1
xneiap = xneiap Grrrrrrrrrrrrrrrr