https://s.wordpress.com/latex.php?latex=%28%5Ccos%20%5Ctheta%20%2Bi%5Csin%20%5Ctheta%20%29%5E%7B3%7D%3D%5Ccos%203%5Ctheta%20%2B%20i%5Csin%203%5Ctheta%20&bg=FFFFFF&fg=000000&s=0