2.1.2 So­lu­tion math­c­plx-b

Ques­tion:

Show more di­rectly that 1$\raisebox{.5pt}{$/$}$​${\rm i}$ $\vphantom0\raisebox{1.5pt}{$=$}$ $\vphantom{0}\raisebox{1.5pt}{$-$}$${\rm i}$.

An­swer:

The prob­a­bly most straight­for­ward way is to take ${\rm i}$ to the other side, 1 $\vphantom0\raisebox{1.5pt}{$=$}$ $\vphantom{0}\raisebox{1.5pt}{$-$}$${\rm i}^2$, and then note that ${\rm i}^2$ $\vphantom0\raisebox{1.5pt}{$=$}$ $\vphantom{0}\raisebox{1.5pt}{$-$}$1.