Question

комплексные числа

i^40-i^21=

Answer 1

$i^{40}-i^{21}=\ i^{4*10}-i^{20+1}=\ (i^4)^{10}-i^{20}*i=\ 1^{10}-i^{4*5}*i=\ 1-(i^4)^{5}*i=\ 1-1^5 *i=1-i$