Step-by-step explanation:
10.
First, convert 1+i from Cartesian to polar.
r = √(1² + 1²)
r = √2
θ = atan(1/1), θ in first quadrant
θ = 45°
Therefore:
(1+i)²⁰ = (√2 (cos 45° + i sin 45°))²⁰
(1+i)²⁰ = 1024 (cos 45° + i sin 45°)²⁰
Now applying the De Moivre theorem:
1024 (cos (20×45°) + i sin (20×45°))
1024 (cos (900°) + i sin (900°))
1024 (-1 + 0)
-1024
11.
Repeat the same steps from Question 10. First, convert to polar:
r = √(1² + (-1)²)
r = √2
θ = atan(-1/1), θ in fourth quadrant
θ = 315°
Therefore:
(1−i)¹⁰ = (√2 (cos 315° + i sin 315°))¹⁰
(1−i)¹⁰ = 32 (cos 315° + i sin 315°)¹⁰
Now applying the De Moivre theorem:
32 (cos (10×315°) + i sin (10×315°))
32 (cos (3150°) + i sin (3150°))
32 (0 − i)
-32i
