Question

[Nguyen Thi Ngoc Lan]

viet cac tap hop sau bang cach liet ke cac phan tu cua tap hop do

A = { x ϵ N / x < 12 }

B = { y ϵ N / 11 < y < 20 }

C = {z ϵ N / z = m ( m + 1 ) ; m = 0 ; 1 ; 2 ; 3 }

Answer 1

[Lê Yến My]

A={x\(\in\)N/ x<12}

=> A={0;1;2;3;4;5;6;7;8;9;10;11}

B={y\(\in\)N/ 11<y<20}

=>B={12;13;14;15;16;17;18;19}

C={z\(\in\) N/z=m (m+1);m=0;1;2;3}

=> C={0;2;4;6}

Answer 2

[Trịnh Thị Thúy Vân]

A = { x \(\in\) N / x < 12 }

=> A = { 0 ; 1 ; 2 ; 3 ; 4 ; ... ; 10 ; 11 }

B = { y \(\in\) N / 11 < y < 20 }

=> B = { 12 ; 13 ; ... ; 18 ; 19 }

C = { z \(\in\) N / m(m+1) ; m = 0 ; 1 ; 2 ; 3 }

+) Nếu m = 0

=> m(m+1) = 0.(0+1) = 0.1=0

+) Nếu m = 1

=> m(m+1) = 1 . ( 1 + 1 ) = 1 . 2 = 2

+) Nếu m = 2

=> m(m+1) = 2.(2+1) = 2.3=6

+) Nếu m = 3

=> m(m+1) = 3.(3+1) = 3. 4 = 12

Vậy C = { 0 ; 2 ; 6 ; 12 }