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        "value": "def f(x):\n    return 2 * x**2 + 3\nx = 3.0 # derivative point\nh = 0.1 # differential step\nNp = 3 # point number for central derivative\nweights = _central_diff_weights(Np) # weights for first derivative\nvals = [f(x + (i - Np/2) * h) for i in range(Np)]\n",
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        "value": "sum(w * v for (w, v) in zip(weights, vals))/h\n",
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        "value": "\nThis value is close to the analytical solution:\nf'(x) = 4x, so f'(3) = 12"
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