Question

Answer 1

Câu 4: 

`a) A = {x ∈ N | 0<=x<=4}`

`b) B = {x ∈ N | x=2k (k in N); x<=16}`

`c) C = {x ∈ Z | x= (-3)^k; k in N`*`; k <5 }`

`d) D = {x in N`*`| x = (3k)^2; k in N`*`;  k <5} `

`e) E = {x in N`*`| (1;x) = 1 ; 2 <=x <= 11}`

`f) F = {x in N`*` | x vdots 3; 3 <= x <= 15}`

Answer 2

Câu 5: 

`a) A = {1;4;9;16;25;36;...}`

`b) B = {+-1;+-2;+-3;+-4;+-6;+-12}`

`c) C = {0;+-120;+-240;+-360;....}`