E&P 5.3.8PkkkZGVxRzYiLywoLUklZGlmZkclKnByb3RlY3RlZEc2JS1JInlHRiQ2I0kieEdGJEYuRi4iIiItRig2JEYrRi4hIidGKyIjOCIiIQ==LUknZHNvbHZlRzYiNiRJJGRlcUdGJC1JInlHRiQ2I0kieEdGJA==if you wanted time as the independent variable you just have to use explicit function notation:PkkkZGVxRzYiLywoLS0tSSNAQEc2JCUqcHJvdGVjdGVkR0koX3N5c2xpYkdGJDYkSSJER0YrIiIjNiNJInlHRiQ2I0kidEdGJCIiIi0tRi9GMUYzISInLUYyRjMiIzgiIiE=LUknZHNvbHZlRzYkJSpwcm90ZWN0ZWRHSShfc3lzbGliRzYiNiRJJGRlcUdGJy1JInlHRic2I0kidEdGJw==The only difference is that the output uses the D notation for the derivative instead of the d/dx notation.