Question

Wyznacz A⋃ B,A⋂ B,A\B,B\A jeżeli : a) A-zbiór liczb pierwszych nie większych od 25 B={x∈ C:(2x-4)≲ 10} b) A=(-∞ ,6) B=(-5,20)

Answer 1

a)

A = { 2,3,5,7,11,13,17,19,23 }

B = { -3,-2,-1,0,1,2,3,4,5,6,7 }

bo

I 2x - 4 I < = 10 

2x - 4 < = 10  i  2x - 4 > = - 10

2x <= 14  i    2x > = - 6

x <= 7      i     x > = - 3

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A u B = { -3,-2,-1,0,1,2,3,4,5,6,7,11,13,17,19,23 }

A n B = { 2,3,5,7 }

A \ B = { 11,13,17,19,23 }

B \ A = { -3,-2,-1,0,1,4,6 }

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b)

A = ( -oo; 6 )

B = (- 5; 20 )

A u B = ( -oo; 20 )

A n B = ( - 5; 6 )

A \ B = ( - oo; - 5 >

B \ A = < 6; 20 )

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