1. A = {1,2,3}, B = {3,4}, Find A cross B ...

Solution:
Here `A={1,2,3},B={3,4}`

`A × B = {1,2,3} × {3,4}`

`= { (1,3), (1,4), (2,3), (2,4), (3,3), (3,4)}`

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2. A = {1,2,3,4}, B = {a,b,c}, Find A cross B ...

Solution:
Here `A={1,2,3,4},B={a,b,c}`

`A × B = {1,2,3,4} × {a,b,c}`

`= { (1,a), (1,b), (1,c), (2,a), (2,b), (2,c), (3,a), (3,b), (3,c), (4,a), (4,b), (4,c)}`

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3. A = {x<=5; x in N}, B = {2<=x<=8; x in N}, C = {x<=3; x in N}, Find A cross (B intersect C) ...

Solution:
`A={x<=5; x in N}`
`:.A={1,2,3,4,5}`

`B={2<=x<=8; x in N}`
`:.B={2,3,4,5,6,7,8}`

`C={x<=3; x in N}`
`:.C={1,2,3}`

`B nn C = {2,3,4,5,6,7,8} nn {1,2,3}`

`= {color{red}{2},color{green}{3},4,5,6,7,8} nn {1,color{red}{2},color{green}{3}}`

`= {2,3}`

`A × (B ∩ C) = {1,2,3,4,5} × {2,3}`

`= { (1,2), (1,3), (2,2), (2,3), (3,2), (3,3), (4,2), (4,3), (5,2), (5,3)}`

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