find the dimension of the given space?
up vote
0
down vote
favorite
let $W_1$ be the real vector space of all $5 times 2$ matrices of such that the sum the sum of the entries in each row is $0 $. let $W_2$be the real vector space of all $5 times 2$ matrices such that the sum of the entries in each column is zero .find the dimension of the space $W _1 cap W_2$
my attempts :$max[0,dim(W_1)+dim(W_2)- 5] le dim(W_1 ∩ W_2) le min[ dim(W_1) ,dim (W_2),]$
so $dim(W_1 ∩ W_2) = 2$
Am i right ?
linear-algebra
add a comment |
up vote
0
down vote
favorite
let $W_1$ be the real vector space of all $5 times 2$ matrices of such that the sum the sum of the entries in each row is $0 $. let $W_2$be the real vector space of all $5 times 2$ matrices such that the sum of the entries in each column is zero .find the dimension of the space $W _1 cap W_2$
my attempts :$max[0,dim(W_1)+dim(W_2)- 5] le dim(W_1 ∩ W_2) le min[ dim(W_1) ,dim (W_2),]$
so $dim(W_1 ∩ W_2) = 2$
Am i right ?
linear-algebra
1
You are not. I suppose that You calculate $dim(W_1)$ and $dim(W_2)$ in a wrong way. $dim(W_2)$ is much larger than $2$.
– Logic_Problem_42
May 8 at 5:34
1
I think the answer is 4. A row vector sums to 0 means it must have dimension 4. And since the columns sum to 0 once the first row is fixed the next row is negative of the first row.
– Piyush Divyanakar
May 8 at 5:38
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
let $W_1$ be the real vector space of all $5 times 2$ matrices of such that the sum the sum of the entries in each row is $0 $. let $W_2$be the real vector space of all $5 times 2$ matrices such that the sum of the entries in each column is zero .find the dimension of the space $W _1 cap W_2$
my attempts :$max[0,dim(W_1)+dim(W_2)- 5] le dim(W_1 ∩ W_2) le min[ dim(W_1) ,dim (W_2),]$
so $dim(W_1 ∩ W_2) = 2$
Am i right ?
linear-algebra
let $W_1$ be the real vector space of all $5 times 2$ matrices of such that the sum the sum of the entries in each row is $0 $. let $W_2$be the real vector space of all $5 times 2$ matrices such that the sum of the entries in each column is zero .find the dimension of the space $W _1 cap W_2$
my attempts :$max[0,dim(W_1)+dim(W_2)- 5] le dim(W_1 ∩ W_2) le min[ dim(W_1) ,dim (W_2),]$
so $dim(W_1 ∩ W_2) = 2$
Am i right ?
linear-algebra
linear-algebra
edited Nov 15 at 16:00
asked May 8 at 5:30
jasmine
1,331416
1,331416
1
You are not. I suppose that You calculate $dim(W_1)$ and $dim(W_2)$ in a wrong way. $dim(W_2)$ is much larger than $2$.
– Logic_Problem_42
May 8 at 5:34
1
I think the answer is 4. A row vector sums to 0 means it must have dimension 4. And since the columns sum to 0 once the first row is fixed the next row is negative of the first row.
– Piyush Divyanakar
May 8 at 5:38
add a comment |
1
You are not. I suppose that You calculate $dim(W_1)$ and $dim(W_2)$ in a wrong way. $dim(W_2)$ is much larger than $2$.
– Logic_Problem_42
May 8 at 5:34
1
I think the answer is 4. A row vector sums to 0 means it must have dimension 4. And since the columns sum to 0 once the first row is fixed the next row is negative of the first row.
– Piyush Divyanakar
May 8 at 5:38
1
1
You are not. I suppose that You calculate $dim(W_1)$ and $dim(W_2)$ in a wrong way. $dim(W_2)$ is much larger than $2$.
– Logic_Problem_42
May 8 at 5:34
You are not. I suppose that You calculate $dim(W_1)$ and $dim(W_2)$ in a wrong way. $dim(W_2)$ is much larger than $2$.
– Logic_Problem_42
May 8 at 5:34
1
1
I think the answer is 4. A row vector sums to 0 means it must have dimension 4. And since the columns sum to 0 once the first row is fixed the next row is negative of the first row.
– Piyush Divyanakar
May 8 at 5:38
I think the answer is 4. A row vector sums to 0 means it must have dimension 4. And since the columns sum to 0 once the first row is fixed the next row is negative of the first row.
– Piyush Divyanakar
May 8 at 5:38
add a comment |
1 Answer
1
active
oldest
votes
up vote
4
down vote
accepted
Elements of $W_1 cap W_2$ satisfy the condition that the sum of each row and each column is $0$.
Hence the first row completely determines the next row and the first $4$ entries of the first row would determine the $5$ element, hence the dimension is $4$.
thanks Siong THye
– jasmine
May 8 at 7:43
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
4
down vote
accepted
Elements of $W_1 cap W_2$ satisfy the condition that the sum of each row and each column is $0$.
Hence the first row completely determines the next row and the first $4$ entries of the first row would determine the $5$ element, hence the dimension is $4$.
thanks Siong THye
– jasmine
May 8 at 7:43
add a comment |
up vote
4
down vote
accepted
Elements of $W_1 cap W_2$ satisfy the condition that the sum of each row and each column is $0$.
Hence the first row completely determines the next row and the first $4$ entries of the first row would determine the $5$ element, hence the dimension is $4$.
thanks Siong THye
– jasmine
May 8 at 7:43
add a comment |
up vote
4
down vote
accepted
up vote
4
down vote
accepted
Elements of $W_1 cap W_2$ satisfy the condition that the sum of each row and each column is $0$.
Hence the first row completely determines the next row and the first $4$ entries of the first row would determine the $5$ element, hence the dimension is $4$.
Elements of $W_1 cap W_2$ satisfy the condition that the sum of each row and each column is $0$.
Hence the first row completely determines the next row and the first $4$ entries of the first row would determine the $5$ element, hence the dimension is $4$.
answered May 8 at 6:23
Siong Thye Goh
94.3k1462114
94.3k1462114
thanks Siong THye
– jasmine
May 8 at 7:43
add a comment |
thanks Siong THye
– jasmine
May 8 at 7:43
thanks Siong THye
– jasmine
May 8 at 7:43
thanks Siong THye
– jasmine
May 8 at 7:43
add a comment |
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2771706%2ffind-the-dimension-of-the-given-space%23new-answer', 'question_page');
}
);
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Sign up or log in
StackExchange.ready(function () {
StackExchange.helpers.onClickDraftSave('#login-link');
});
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Sign up using Google
Sign up using Facebook
Sign up using Email and Password
Post as a guest
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
Required, but never shown
1
You are not. I suppose that You calculate $dim(W_1)$ and $dim(W_2)$ in a wrong way. $dim(W_2)$ is much larger than $2$.
– Logic_Problem_42
May 8 at 5:34
1
I think the answer is 4. A row vector sums to 0 means it must have dimension 4. And since the columns sum to 0 once the first row is fixed the next row is negative of the first row.
– Piyush Divyanakar
May 8 at 5:38