SOLUTION: If V={v1,v2,...,vk} is linearly independent, and w is not element of V. Then show that {v1+w,v2+w,...,vk+w} is linearly independent

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Question 455735: If V={v1,v2,...,vk} is linearly independent, and w is not element of V. Then show that {v1+w,v2+w,...,vk+w} is linearly independent
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
Let w+=+v%5B1%5D+%2B+v%5B2%5D +...+v%5Bk%5D.
Now let
a%5B1%5D%2A%28v%5B1%5D+%2B+w%29+%2B+a%5B2%5D%2A%28v%5B2%5D++%2B+w%29+...+a%5Bk%5D%2A%28v%5Bk%5D+%2B+w%29 = theta,
which for the purpose of contradiction, we assume that not all the a's are 0, (i.e., the set is linearly DEPENDENT).

==> (2a%5B1%5D+%2B+a%5B2%5D+...+a%5Bk%5D)*v%5B1%5D
+(a%5B1%5D+%2B+2a%5B2%5D+...+a%5Bk%5D)*v%5B2%5D + ...+(a%5B1%5D+%2B+a%5B2%5D+...+2a%5Bk%5D)*v%5Bk%5D = theta
By the hypothesis, {v1, v2, v3,..., vk } is linearly independent, and thus,
2a%5B1%5D+%2B+a%5B2%5D+...+a%5Bk%5D+=+0
a%5B1%5D+%2B+2a%5B2%5D+...+a%5Bk%5D+=+0
...................................
a%5B1%5D+%2B+a%5B2%5D+...+2a%5Bk%5D+=+0.
We get a homogeneous system of equations.
Adding all corresponding sides of the system, we get
%28k%2B1%29a%5B1%5D+%2B+%28k%2B1%29a%5B2%5D+...+%28k%2B1%29a%5Bk%5D+=+0
OR,
a%5B1%5D+%2B+a%5B2%5D+...+a%5Bk%5D+=+0.
Subtracting this equation from each one of the equations in the system above, we obtain
a%5B1%5D+=+a%5B2%5D+=+a%5B3%5D=...=a%5Bk%5D+=+0,
CONTRARY to the initial assumption that not all a's are 0.
Hence {v1+w,v2+w,...,vk+w} must be linearly independent.