ответ: α * β = 12(cos7π/12 + i sin7π/12) .
Объяснение:
. . . α * β = 3*4*(cosπ/4 + i sinπ/4 )*( cosπ/3 + i sinπ/3 ) = 12(cosπ/4cosπ/3 +
+ i cosπ/4sinπ/3 + i sinπ/4cosπ/3 + i²sinπ/4sinπ/3 ) = 12 [( cosπ/4cosπ/3 -
- sinπ/4sinπ/3 ) + i ( sinπ/3cosπ/4 + cosπ/3sinπ/4 ) ] = 12 [ (cos(π/3 + π/4 ) +
+ i sin( π/3 + π/4 ) ] = 12(cos7π/12 + i sin7π/12) .
