Question

determinati elementele multimii A ={x∈N|2≤√x<5}
B={x∈N|-3≤-√x≤40}
C={x∈N|48≤3x²≤108}
D={x∈Z|24≤x²≤49}

Answer 1

A ={x∈N|2≤√x<5}

2≤√4  si√24 <5

A={4, 5, 6, 7, ……,24}

B={x∈N|-3≤-√x≤40}

3≥√x => x∈{0,1,2,3…9}; -√x≤40, oricare ar fi x∈N

B={0, 1, 2, 3, 4, …,9}

C={x∈N|48≤3x²≤108}

48≤3x²≤108 <=> 16≤x²≤36

C={4, 5, 6}

D={x∈Z|24≤x²≤49}

D={-7, -6, -5, 5, 6, 7}