- #1
lavster
- 217
- 0
hey, can someone show me the step between these two lines of equations please:
[tex](\Delta A)^2=<\psi|A^2|\psi>-<\psi|A|\psi>^2[/tex]
[tex]=<\psi|(A-<A>)^2|\psi>[/tex]
where A is an operator and [tex]\psi[/tex] is the wavefunction and [tex]<A>[/tex] is the expectation value of A
[tex](\Delta A)^2=<\psi|A^2|\psi>-<\psi|A|\psi>^2[/tex]
[tex]=<\psi|(A-<A>)^2|\psi>[/tex]
where A is an operator and [tex]\psi[/tex] is the wavefunction and [tex]<A>[/tex] is the expectation value of A