1. Examples
1. A = {1,2,3,4}, B = {3,4,5}, Find A union B ...
Solution:
Here `A={1,2,3,4},B={3,4,5}`
`A uu B = {1,2,3,4} uu {3,4,5}`
`= {1,2,color{red}{3},color{green}{4}} uu {color{red}{3},color{green}{4},5}`
`= {1,2,3,4,5}`
2. A = {x<=5; x in N}, B = {2<=x<=8; x in N}, Find A union B ...
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}`
`A uu B = {1,2,3,4,5} uu {2,3,4,5,6,7,8}`
`= {1,color{red}{2},color{green}{3},color{blue}{4},color{maroon}{5}} uu {color{red}{2},color{green}{3},color{blue}{4},color{maroon}{5},6,7,8}`
`= {1,2,3,4,5,6,7,8}`
3. A = {x<=5; x in N}, B = {2<=x<=8; x in N}, C = {x<=3; x in N}, Prove that A union (B union C) = (A union B) union 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}`
To find LHS = `A uu (B uu C)`
`B uu C = {2,3,4,5,6,7,8} uu {1,2,3}`
`= {color{red}{2},color{green}{3},4,5,6,7,8} uu {1,color{red}{2},color{green}{3}}`
`= {2,3,4,5,6,7,8,1}`
`A uu (B uu C) = {1,2,3,4,5} uu {2,3,4,5,6,7,8,1}`
`= {color{red}{1},color{green}{2},color{blue}{3},color{maroon}{4},color{fuchsia}{5}} uu {color{green}{2},color{blue}{3},color{maroon}{4},color{fuchsia}{5},6,7,8,color{red}{1}}`
`= {1,2,3,4,5,6,7,8}`
`:. A uu (B uu C) = {1,2,3,4,5,6,7,8} ->(1)`
To find RHS = `(A uu B) uu C`
`A uu B = {1,2,3,4,5} uu {2,3,4,5,6,7,8}`
`= {1,color{red}{2},color{green}{3},color{blue}{4},color{maroon}{5}} uu {color{red}{2},color{green}{3},color{blue}{4},color{maroon}{5},6,7,8}`
`= {1,2,3,4,5,6,7,8}`
`(A uu B) uu C = {1,2,3,4,5,6,7,8} uu {1,2,3}`
`= {color{red}{1},color{green}{2},color{blue}{3},4,5,6,7,8} uu {color{red}{1},color{green}{2},color{blue}{3}}`
`= {1,2,3,4,5,6,7,8}`
`:. (A uu B) uu C = {1,2,3,4,5,6,7,8} ->(2)`
From (1) and (2)
`:. A uu (B uu C) = (A uu B) uu C` (proved)
This material is intended as a summary. Use your textbook for detail explanation.
Any bug, improvement, feedback then
|
