current is defined as the flow of positive charge. Specifically:

\begin{equation} I = \frac{\Delta Q}{\Delta t} \end{equation}

resistance of a wire

(if ever you come across needing to calculate the resistance of the wire from scratch)

\begin{equation} R = \rho \frac{L}{A} \end{equation}

where, \(\rho\) is the material resistivity, \(L\) the length, and \(A\) the cross-sectional area.

you rarely need to do this!

The curse of dimensionality is the result of correlatives of the fact that:

at higher dimensions, most random data points become equidistant from each other — you can prove this to yourself pythagoras and some math of expectation

1. random vectors are almost orthogonal
2. unit sphere takes almost no volume in unit square (?)

User Stories but harder and more rigerous: https://www.visual-paradigm.com/guide/customer-experience/what-is-customer-journey-mapping/