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Math Help - commutators

  1. #1
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    commutators

    evaluate the commutator [-d^2 / dx^2 , x] f (x)

    can anyone please check my work thanks.

    [-d^2 / dx^2 , x] f (x) = -2f '(x) -xf "(x) + -xf "(x)

    [-d^2 / dx^2 , x] f (x) = -2f '(x) = -2 (d/dx (f(x))

    [-d^2 / dx^2 , x] = -2 d/dx
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  2. #2
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    Quote Originally Posted by myoplex11 View Post
    evaluate the commutator [-d^2 / dx^2 , x] f (x)

    can anyone please check my work thanks.

    [-d^2 / dx^2 , x] f (x) = -2f '(x) -xf "(x) + -xf "(x)

    [-d^2 / dx^2 , x] f (x) = -2f '(x) = -2 (d/dx (f(x))

    [-d^2 / dx^2 , x] = -2 d/dx
    There's a typo in the first line (the last term should be +xf''(x).) Otherwise it looks good.

    -Dan
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