#z^5 = sqrt 2 (sqrt2 /2 + i sqrt 2/2)#
#z^5 = sqrt 2 (cos frac{pi}{4} + i sin frac{pi}{4})#
#z = root[10]{2}(cos frac{pi/4 + 2kpi}{5} + i sin frac{pi/4 + 2kpi}{5});
k = 0, 1, 2, 3, 4#
#z = root[10]{2}(cos frac{pi+8kpi}{20} + i sin frac{pi+8kpi}{20}); k = 0, 1, 2, 3, 4#