How to show that the set $W=(x,y,z):x+y=0$ is a subspace of the vector space $V_3(mathbbR)$? [closed]

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Let alpha=(x,y,z) and beta=(u,v,w) be any two elements of W.
Then x,y,z,u,v,w are the elements of R and are such that
($x+u=0).....(1)
($y+v=0)......(2)
($z+w=0).....(3)
$If a,b be any two elements of R,we have
a $alpha+ b beta=a(x,y,z)+b(u,v,w)
=(ax+bu),(ay+bv),(az+bw)
Now,. ax+bu+ay+bv+az+bw=a(x+y+z)+b(u+v+w)??



This is the way I did this question,where I went wrong?







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closed as off-topic by Alex Francisco, Leucippus, Shailesh, Delta-u, max_zorn Jul 17 at 7:36


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Alex Francisco, Leucippus, Shailesh, Delta-u, max_zorn
If this question can be reworded to fit the rules in the help center, please edit the question.












  • A subset of a vector space needs to fulfill three simple rules in order to be a subspace. Do you know what those rules are?
    – Arthur
    Jul 17 at 6:30






  • 1




    Zero vector should be in the set W.
    – Anurag Malik
    Jul 17 at 6:31











  • Good, that's rule 1. Now, is the zero vector in the set $W$?
    – Arthur
    Jul 17 at 6:33










  • Scalar multiplication and vector addition.
    – Anurag Malik
    Jul 17 at 6:33










  • That's rule 2 and 3. So, 2) if you add two vectors from $W$, is the result still always in $W$, no matter which two vectors you added? And 3) if you scale a vector from $W$, is the result in $W$ no matter which vector you started with and which scalar you used? Those are the questions you need to answer. And we would really appreciate it if you edited your question post to show what you have tried for each rule.
    – Arthur
    Jul 17 at 6:35















up vote
-1
down vote

favorite












Let alpha=(x,y,z) and beta=(u,v,w) be any two elements of W.
Then x,y,z,u,v,w are the elements of R and are such that
($x+u=0).....(1)
($y+v=0)......(2)
($z+w=0).....(3)
$If a,b be any two elements of R,we have
a $alpha+ b beta=a(x,y,z)+b(u,v,w)
=(ax+bu),(ay+bv),(az+bw)
Now,. ax+bu+ay+bv+az+bw=a(x+y+z)+b(u+v+w)??



This is the way I did this question,where I went wrong?







share|cite|improve this question













closed as off-topic by Alex Francisco, Leucippus, Shailesh, Delta-u, max_zorn Jul 17 at 7:36


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Alex Francisco, Leucippus, Shailesh, Delta-u, max_zorn
If this question can be reworded to fit the rules in the help center, please edit the question.












  • A subset of a vector space needs to fulfill three simple rules in order to be a subspace. Do you know what those rules are?
    – Arthur
    Jul 17 at 6:30






  • 1




    Zero vector should be in the set W.
    – Anurag Malik
    Jul 17 at 6:31











  • Good, that's rule 1. Now, is the zero vector in the set $W$?
    – Arthur
    Jul 17 at 6:33










  • Scalar multiplication and vector addition.
    – Anurag Malik
    Jul 17 at 6:33










  • That's rule 2 and 3. So, 2) if you add two vectors from $W$, is the result still always in $W$, no matter which two vectors you added? And 3) if you scale a vector from $W$, is the result in $W$ no matter which vector you started with and which scalar you used? Those are the questions you need to answer. And we would really appreciate it if you edited your question post to show what you have tried for each rule.
    – Arthur
    Jul 17 at 6:35













up vote
-1
down vote

favorite









up vote
-1
down vote

favorite











Let alpha=(x,y,z) and beta=(u,v,w) be any two elements of W.
Then x,y,z,u,v,w are the elements of R and are such that
($x+u=0).....(1)
($y+v=0)......(2)
($z+w=0).....(3)
$If a,b be any two elements of R,we have
a $alpha+ b beta=a(x,y,z)+b(u,v,w)
=(ax+bu),(ay+bv),(az+bw)
Now,. ax+bu+ay+bv+az+bw=a(x+y+z)+b(u+v+w)??



This is the way I did this question,where I went wrong?







share|cite|improve this question













Let alpha=(x,y,z) and beta=(u,v,w) be any two elements of W.
Then x,y,z,u,v,w are the elements of R and are such that
($x+u=0).....(1)
($y+v=0)......(2)
($z+w=0).....(3)
$If a,b be any two elements of R,we have
a $alpha+ b beta=a(x,y,z)+b(u,v,w)
=(ax+bu),(ay+bv),(az+bw)
Now,. ax+bu+ay+bv+az+bw=a(x+y+z)+b(u+v+w)??



This is the way I did this question,where I went wrong?









share|cite|improve this question












share|cite|improve this question




share|cite|improve this question








edited Jul 19 at 5:34
























asked Jul 17 at 6:24









Anurag Malik

12




12




closed as off-topic by Alex Francisco, Leucippus, Shailesh, Delta-u, max_zorn Jul 17 at 7:36


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Alex Francisco, Leucippus, Shailesh, Delta-u, max_zorn
If this question can be reworded to fit the rules in the help center, please edit the question.




closed as off-topic by Alex Francisco, Leucippus, Shailesh, Delta-u, max_zorn Jul 17 at 7:36


This question appears to be off-topic. The users who voted to close gave this specific reason:


  • "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Alex Francisco, Leucippus, Shailesh, Delta-u, max_zorn
If this question can be reworded to fit the rules in the help center, please edit the question.











  • A subset of a vector space needs to fulfill three simple rules in order to be a subspace. Do you know what those rules are?
    – Arthur
    Jul 17 at 6:30






  • 1




    Zero vector should be in the set W.
    – Anurag Malik
    Jul 17 at 6:31











  • Good, that's rule 1. Now, is the zero vector in the set $W$?
    – Arthur
    Jul 17 at 6:33










  • Scalar multiplication and vector addition.
    – Anurag Malik
    Jul 17 at 6:33










  • That's rule 2 and 3. So, 2) if you add two vectors from $W$, is the result still always in $W$, no matter which two vectors you added? And 3) if you scale a vector from $W$, is the result in $W$ no matter which vector you started with and which scalar you used? Those are the questions you need to answer. And we would really appreciate it if you edited your question post to show what you have tried for each rule.
    – Arthur
    Jul 17 at 6:35

















  • A subset of a vector space needs to fulfill three simple rules in order to be a subspace. Do you know what those rules are?
    – Arthur
    Jul 17 at 6:30






  • 1




    Zero vector should be in the set W.
    – Anurag Malik
    Jul 17 at 6:31











  • Good, that's rule 1. Now, is the zero vector in the set $W$?
    – Arthur
    Jul 17 at 6:33










  • Scalar multiplication and vector addition.
    – Anurag Malik
    Jul 17 at 6:33










  • That's rule 2 and 3. So, 2) if you add two vectors from $W$, is the result still always in $W$, no matter which two vectors you added? And 3) if you scale a vector from $W$, is the result in $W$ no matter which vector you started with and which scalar you used? Those are the questions you need to answer. And we would really appreciate it if you edited your question post to show what you have tried for each rule.
    – Arthur
    Jul 17 at 6:35
















A subset of a vector space needs to fulfill three simple rules in order to be a subspace. Do you know what those rules are?
– Arthur
Jul 17 at 6:30




A subset of a vector space needs to fulfill three simple rules in order to be a subspace. Do you know what those rules are?
– Arthur
Jul 17 at 6:30




1




1




Zero vector should be in the set W.
– Anurag Malik
Jul 17 at 6:31





Zero vector should be in the set W.
– Anurag Malik
Jul 17 at 6:31













Good, that's rule 1. Now, is the zero vector in the set $W$?
– Arthur
Jul 17 at 6:33




Good, that's rule 1. Now, is the zero vector in the set $W$?
– Arthur
Jul 17 at 6:33












Scalar multiplication and vector addition.
– Anurag Malik
Jul 17 at 6:33




Scalar multiplication and vector addition.
– Anurag Malik
Jul 17 at 6:33












That's rule 2 and 3. So, 2) if you add two vectors from $W$, is the result still always in $W$, no matter which two vectors you added? And 3) if you scale a vector from $W$, is the result in $W$ no matter which vector you started with and which scalar you used? Those are the questions you need to answer. And we would really appreciate it if you edited your question post to show what you have tried for each rule.
– Arthur
Jul 17 at 6:35





That's rule 2 and 3. So, 2) if you add two vectors from $W$, is the result still always in $W$, no matter which two vectors you added? And 3) if you scale a vector from $W$, is the result in $W$ no matter which vector you started with and which scalar you used? Those are the questions you need to answer. And we would really appreciate it if you edited your question post to show what you have tried for each rule.
– Arthur
Jul 17 at 6:35











1 Answer
1






active

oldest

votes

















up vote
0
down vote



accepted










You have to show: if $(x,y,z), (u,v,w) in W$ and $ alpha in mathbb R$ then



$(x+u,y+v,z+w) in W$ and $(alpha x,alpha y,alpha z) in W$.






share|cite|improve this answer





















  • You're forgetting $0in W$. Which assuming your properties is really equivalent to $Wneqvarnothing$, so it's quite trivial. Nevertheless it must be pointed out of a proof is to be complete.
    – Arthur
    Jul 17 at 6:41

















1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
0
down vote



accepted










You have to show: if $(x,y,z), (u,v,w) in W$ and $ alpha in mathbb R$ then



$(x+u,y+v,z+w) in W$ and $(alpha x,alpha y,alpha z) in W$.






share|cite|improve this answer





















  • You're forgetting $0in W$. Which assuming your properties is really equivalent to $Wneqvarnothing$, so it's quite trivial. Nevertheless it must be pointed out of a proof is to be complete.
    – Arthur
    Jul 17 at 6:41














up vote
0
down vote



accepted










You have to show: if $(x,y,z), (u,v,w) in W$ and $ alpha in mathbb R$ then



$(x+u,y+v,z+w) in W$ and $(alpha x,alpha y,alpha z) in W$.






share|cite|improve this answer





















  • You're forgetting $0in W$. Which assuming your properties is really equivalent to $Wneqvarnothing$, so it's quite trivial. Nevertheless it must be pointed out of a proof is to be complete.
    – Arthur
    Jul 17 at 6:41












up vote
0
down vote



accepted







up vote
0
down vote



accepted






You have to show: if $(x,y,z), (u,v,w) in W$ and $ alpha in mathbb R$ then



$(x+u,y+v,z+w) in W$ and $(alpha x,alpha y,alpha z) in W$.






share|cite|improve this answer













You have to show: if $(x,y,z), (u,v,w) in W$ and $ alpha in mathbb R$ then



$(x+u,y+v,z+w) in W$ and $(alpha x,alpha y,alpha z) in W$.







share|cite|improve this answer













share|cite|improve this answer



share|cite|improve this answer











answered Jul 17 at 6:39









Fred

37.6k1237




37.6k1237











  • You're forgetting $0in W$. Which assuming your properties is really equivalent to $Wneqvarnothing$, so it's quite trivial. Nevertheless it must be pointed out of a proof is to be complete.
    – Arthur
    Jul 17 at 6:41
















  • You're forgetting $0in W$. Which assuming your properties is really equivalent to $Wneqvarnothing$, so it's quite trivial. Nevertheless it must be pointed out of a proof is to be complete.
    – Arthur
    Jul 17 at 6:41















You're forgetting $0in W$. Which assuming your properties is really equivalent to $Wneqvarnothing$, so it's quite trivial. Nevertheless it must be pointed out of a proof is to be complete.
– Arthur
Jul 17 at 6:41




You're forgetting $0in W$. Which assuming your properties is really equivalent to $Wneqvarnothing$, so it's quite trivial. Nevertheless it must be pointed out of a proof is to be complete.
– Arthur
Jul 17 at 6:41


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