Answer
$ -1264-286.2167i$
Work Step by Step
Based on the given conditions, we have:
$(1-\sqrt 5i)^8\\ \approx[\sqrt 6(cos294.0948426^\circ+i\ sin294.0948426^\circ)]^8\\ \approx1296(cos2352.75874^\circ+i\ sin2352.75874^\circ)\\ \approx1296(-0.975308642-0.2208462129i)\\ \approx-1264-286.2167i$