Răspuns:
A = {1; 3; 5; 7}
B = {1; 2; 4; 8}
C = {0; 1; 2; 3; 4; 5}
D = {0; 1; 2}
Explicație:
A = {x | x ∈ N, x = 2k + 1, k ∈ N, k ≤ 3}
k ∈ {0, 1, 2, 3}
⇒ x = 2k + 1 ∈ {2·0+1; 2·1+1; 2·2+1; 2·3+1}
x ∈ {0+1; 2+1; 4+1; 6+1}
A = {1; 3; 5; 7}
B = {x | x ∈ N, x = [tex]2^{k}[/tex], k ∈ N, k < 4}
k ∈ {0, 1, 2, 3}
⇒ x = [tex]2^{k}[/tex] ∈ {2⁰; 2¹; 2²; 2³}
B = {1; 2; 4; 8}
C = {x | x ∈ N, 2ˣ ≤ 32}
2⁵ = 32 ⇒ x ≤ 5
C = {0; 1; 2; 3; 4; 5}
D = {x | x ∈ N, x⁴ ≤ 64}
2⁴ = 16 < 64
3⁴ = 81 > 64
⇒ x ≤ 2
D = {0; 1; 2}
