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rad0786
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Vector Spaces, Subspaces, Bases etc... :(
Hello. I was doing some homework questions out of the textbook and i came across a question which is difficult to understand, could somebody please help me out with it?
-- if U and W are subspaces of V, define their intersection U ∩ W as follows:
U ∩ W = {v / v is in both U and W}
a) show that U ∩ W is a subspace contained in U and W
b) If B and D are bases of U and W, and if U ∩ W = {0}, show that
B U D = {v / v is in B or D} is linearly independent.
--
I was able to do part a)! That wasn't so tricky. You just show that clousre of addition and scalar multiplication hold. (and show that the vectors each belong in U and W etc...)
So i understand part a), but part b) is where I am lost
To begin, I am not sure if "B is a basis of U" and "D is a basis of W"... or is "B and D" a basis of U and "B and D" is a basis of W? I think its the first one.
Next... U ∩ W = {0} means that the zero vector lies in U and lies in W.
Furthermore... B U D has a vector that lies in only B or in only D, and not B ∩ D.
so now is where I don't know how to show that it is linearly independent.
All i know so far is that U ∩ W = {0} has a basis of 1 and that is all i have to work with :( Can somebody please help me further?
Thanks
Hello. I was doing some homework questions out of the textbook and i came across a question which is difficult to understand, could somebody please help me out with it?
-- if U and W are subspaces of V, define their intersection U ∩ W as follows:
U ∩ W = {v / v is in both U and W}
a) show that U ∩ W is a subspace contained in U and W
b) If B and D are bases of U and W, and if U ∩ W = {0}, show that
B U D = {v / v is in B or D} is linearly independent.
--
I was able to do part a)! That wasn't so tricky. You just show that clousre of addition and scalar multiplication hold. (and show that the vectors each belong in U and W etc...)
So i understand part a), but part b) is where I am lost
To begin, I am not sure if "B is a basis of U" and "D is a basis of W"... or is "B and D" a basis of U and "B and D" is a basis of W? I think its the first one.
Next... U ∩ W = {0} means that the zero vector lies in U and lies in W.
Furthermore... B U D has a vector that lies in only B or in only D, and not B ∩ D.
so now is where I don't know how to show that it is linearly independent.
All i know so far is that U ∩ W = {0} has a basis of 1 and that is all i have to work with :( Can somebody please help me further?
Thanks