Answer:
cos(3π/4) + i·sin(3π/4)
Step-by-step explanation:
The number inside parentheses is already in trigonometric form, with a magnitude of 1 and an angle of π/4. The cube of it will have a magnitude that is the cube of 1, and an angle that is 3 times π/4. Hence ...
1(cos(3π/4) +i·sin(3π/4)) . . . . . matches the last choice
