2.1.5 So­lu­tion math­c­plx-e

Ques­tion:

Ver­ify that $(2-3{\rm i})^2$ is still the com­plex con­ju­gate of $(2+3{\rm i})^2$ if both are mul­ti­plied out.

An­swer:

$(2-3{\rm i})^2$ $\vphantom0\raisebox{1.5pt}{$=$}$ $-5-12{\rm i}$ and $(2+3{\rm i})^2$ $\vphantom0\raisebox{1.5pt}{$=$}$ $-5+12{\rm i}$.