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## Converting $\ln|x| = h$ to $x = e^h$

In Kreyszig’s Advanced Engineering Mathematics, section on First-Order ODEs, it is written: $dF/F = p \, dx$ $\ln|F| = h = \int p \, dx$ Therefore, $F = e^h$ However I don’t understand why the absolute value for $F$ is gone. To my understanding, a simplified version of this could […]

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## Another length error using dplyr mutate() and if_else()

I have another problem similar to by previous question here. As it is not exactly the same I have posted it as a new question. I am attempting to add a vector as a new column to a tbl, but my vector is shorter than the number of rows, therefore I am using if_else() to […]