Question 29492:  Let U and V be subspaces of Rn. Prove that the intersection, U n V, is also a subspace of Rn. 
 Answer by venugopalramana(3286)      (Show Source): 
You can  put this solution on YOUR website! Let U and V be subspaces of Rn. Prove that the intersection, U n V, is also a subspace of Rn. 
LET US USE THE FOLLOWING SYMBOLS...E TO SHOW ELEMENT OF. 
LET U INTERSECTION V = W 
1.0 E U AND 0 E V...SO 0 E W...SO W IS NOT EMPTY. 
2.LET A,B BE ELEMENTS OF W AND X,Y BE SCALAR ELEMENTS IN THE FIELD OF RN. 
3.THE ABOVE IMPLIES THAT A,B ARE ELEMENTS OF U .HENCE XA+YB IS AN ELEMENT OF U. 
4.SIMILARLY.......XA+YB IS AN ELEMENT OF V. 
5.HENCE XA+YB IS AN ELEMENT OF W. 
6.THUS WE SHOWED THAT IF A,B ARE ELEMENTS OF W AND X,Y ARE ANY SCALARS IN THE FIELD OF RN  THEN X+YB IS AN ELEMENT OF W. 
7.HENCE W IS A SUBSPACE OF RN. 
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