Dot product with a constant
$begingroup$
What is $vec{a}cdot (vec{b}+c)$, where $c$ is a constant?
Am I able to just take out the constant, or do I multiply the constant by the vector as a scalar?
abstract-algebra vectors
New contributor
$endgroup$
add a comment |
$begingroup$
What is $vec{a}cdot (vec{b}+c)$, where $c$ is a constant?
Am I able to just take out the constant, or do I multiply the constant by the vector as a scalar?
abstract-algebra vectors
New contributor
$endgroup$
$begingroup$
This only makes sense if you make a vector space out of the base field
$endgroup$
– Brevan Ellefsen
1 hour ago
add a comment |
$begingroup$
What is $vec{a}cdot (vec{b}+c)$, where $c$ is a constant?
Am I able to just take out the constant, or do I multiply the constant by the vector as a scalar?
abstract-algebra vectors
New contributor
$endgroup$
What is $vec{a}cdot (vec{b}+c)$, where $c$ is a constant?
Am I able to just take out the constant, or do I multiply the constant by the vector as a scalar?
abstract-algebra vectors
abstract-algebra vectors
New contributor
New contributor
edited 4 hours ago
greedoid
43.5k1154107
43.5k1154107
New contributor
asked 4 hours ago
ItIsLastThursdayItIsLastThursday
212
212
New contributor
New contributor
$begingroup$
This only makes sense if you make a vector space out of the base field
$endgroup$
– Brevan Ellefsen
1 hour ago
add a comment |
$begingroup$
This only makes sense if you make a vector space out of the base field
$endgroup$
– Brevan Ellefsen
1 hour ago
$begingroup$
This only makes sense if you make a vector space out of the base field
$endgroup$
– Brevan Ellefsen
1 hour ago
$begingroup$
This only makes sense if you make a vector space out of the base field
$endgroup$
– Brevan Ellefsen
1 hour ago
add a comment |
2 Answers
2
active
oldest
votes
$begingroup$
This product has no meaning since the sum in the parentheses is undefined; you can not add a vector and a scalar.
$c$ must be a vector, then the sum is defined and the given product is a dot product.
$endgroup$
$begingroup$
So is there any answer I can get?
$endgroup$
– ItIsLastThursday
4 hours ago
6
$begingroup$
No, if $c$ is a scalar then there is no answer.
$endgroup$
– greedoid
4 hours ago
$begingroup$
You can add a vector and a scalar in a more advanced context. This is like when all of my grade school teachers said you couldn't take the square root of a negative number, and I was ahead so I knew they were lying.
$endgroup$
– Matt Samuel
17 mins ago
add a comment |
$begingroup$
For an expression to be defined, all of its constituting parts need to be defined as well.
The sum of a vector and a constant $vec b + c$ is not defined, and hence the expression $vec a cdot (vec b + c)$ is not defined.
This applies to any scalar, not just constants, because $c$ can depend on another variable.
Although it probably makes sense to you that
$$vec a cdot (vec b + c) = vec a cdot vec b + c cdot vec a$$
neither side of the equation is defined, which means that you cannot use distribution the way it was used above.
$endgroup$
$begingroup$
The RHS expression isn't defined either.
$endgroup$
– Hammerite
2 hours ago
$begingroup$
@Hammerite You are right. What a silly mistake. Thank you!
$endgroup$
– Haris Gusic
2 hours ago
add a comment |
Your Answer
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
This product has no meaning since the sum in the parentheses is undefined; you can not add a vector and a scalar.
$c$ must be a vector, then the sum is defined and the given product is a dot product.
$endgroup$
$begingroup$
So is there any answer I can get?
$endgroup$
– ItIsLastThursday
4 hours ago
6
$begingroup$
No, if $c$ is a scalar then there is no answer.
$endgroup$
– greedoid
4 hours ago
$begingroup$
You can add a vector and a scalar in a more advanced context. This is like when all of my grade school teachers said you couldn't take the square root of a negative number, and I was ahead so I knew they were lying.
$endgroup$
– Matt Samuel
17 mins ago
add a comment |
$begingroup$
This product has no meaning since the sum in the parentheses is undefined; you can not add a vector and a scalar.
$c$ must be a vector, then the sum is defined and the given product is a dot product.
$endgroup$
$begingroup$
So is there any answer I can get?
$endgroup$
– ItIsLastThursday
4 hours ago
6
$begingroup$
No, if $c$ is a scalar then there is no answer.
$endgroup$
– greedoid
4 hours ago
$begingroup$
You can add a vector and a scalar in a more advanced context. This is like when all of my grade school teachers said you couldn't take the square root of a negative number, and I was ahead so I knew they were lying.
$endgroup$
– Matt Samuel
17 mins ago
add a comment |
$begingroup$
This product has no meaning since the sum in the parentheses is undefined; you can not add a vector and a scalar.
$c$ must be a vector, then the sum is defined and the given product is a dot product.
$endgroup$
This product has no meaning since the sum in the parentheses is undefined; you can not add a vector and a scalar.
$c$ must be a vector, then the sum is defined and the given product is a dot product.
edited 59 mins ago
Eevee Trainer
6,53811237
6,53811237
answered 4 hours ago
greedoidgreedoid
43.5k1154107
43.5k1154107
$begingroup$
So is there any answer I can get?
$endgroup$
– ItIsLastThursday
4 hours ago
6
$begingroup$
No, if $c$ is a scalar then there is no answer.
$endgroup$
– greedoid
4 hours ago
$begingroup$
You can add a vector and a scalar in a more advanced context. This is like when all of my grade school teachers said you couldn't take the square root of a negative number, and I was ahead so I knew they were lying.
$endgroup$
– Matt Samuel
17 mins ago
add a comment |
$begingroup$
So is there any answer I can get?
$endgroup$
– ItIsLastThursday
4 hours ago
6
$begingroup$
No, if $c$ is a scalar then there is no answer.
$endgroup$
– greedoid
4 hours ago
$begingroup$
You can add a vector and a scalar in a more advanced context. This is like when all of my grade school teachers said you couldn't take the square root of a negative number, and I was ahead so I knew they were lying.
$endgroup$
– Matt Samuel
17 mins ago
$begingroup$
So is there any answer I can get?
$endgroup$
– ItIsLastThursday
4 hours ago
$begingroup$
So is there any answer I can get?
$endgroup$
– ItIsLastThursday
4 hours ago
6
6
$begingroup$
No, if $c$ is a scalar then there is no answer.
$endgroup$
– greedoid
4 hours ago
$begingroup$
No, if $c$ is a scalar then there is no answer.
$endgroup$
– greedoid
4 hours ago
$begingroup$
You can add a vector and a scalar in a more advanced context. This is like when all of my grade school teachers said you couldn't take the square root of a negative number, and I was ahead so I knew they were lying.
$endgroup$
– Matt Samuel
17 mins ago
$begingroup$
You can add a vector and a scalar in a more advanced context. This is like when all of my grade school teachers said you couldn't take the square root of a negative number, and I was ahead so I knew they were lying.
$endgroup$
– Matt Samuel
17 mins ago
add a comment |
$begingroup$
For an expression to be defined, all of its constituting parts need to be defined as well.
The sum of a vector and a constant $vec b + c$ is not defined, and hence the expression $vec a cdot (vec b + c)$ is not defined.
This applies to any scalar, not just constants, because $c$ can depend on another variable.
Although it probably makes sense to you that
$$vec a cdot (vec b + c) = vec a cdot vec b + c cdot vec a$$
neither side of the equation is defined, which means that you cannot use distribution the way it was used above.
$endgroup$
$begingroup$
The RHS expression isn't defined either.
$endgroup$
– Hammerite
2 hours ago
$begingroup$
@Hammerite You are right. What a silly mistake. Thank you!
$endgroup$
– Haris Gusic
2 hours ago
add a comment |
$begingroup$
For an expression to be defined, all of its constituting parts need to be defined as well.
The sum of a vector and a constant $vec b + c$ is not defined, and hence the expression $vec a cdot (vec b + c)$ is not defined.
This applies to any scalar, not just constants, because $c$ can depend on another variable.
Although it probably makes sense to you that
$$vec a cdot (vec b + c) = vec a cdot vec b + c cdot vec a$$
neither side of the equation is defined, which means that you cannot use distribution the way it was used above.
$endgroup$
$begingroup$
The RHS expression isn't defined either.
$endgroup$
– Hammerite
2 hours ago
$begingroup$
@Hammerite You are right. What a silly mistake. Thank you!
$endgroup$
– Haris Gusic
2 hours ago
add a comment |
$begingroup$
For an expression to be defined, all of its constituting parts need to be defined as well.
The sum of a vector and a constant $vec b + c$ is not defined, and hence the expression $vec a cdot (vec b + c)$ is not defined.
This applies to any scalar, not just constants, because $c$ can depend on another variable.
Although it probably makes sense to you that
$$vec a cdot (vec b + c) = vec a cdot vec b + c cdot vec a$$
neither side of the equation is defined, which means that you cannot use distribution the way it was used above.
$endgroup$
For an expression to be defined, all of its constituting parts need to be defined as well.
The sum of a vector and a constant $vec b + c$ is not defined, and hence the expression $vec a cdot (vec b + c)$ is not defined.
This applies to any scalar, not just constants, because $c$ can depend on another variable.
Although it probably makes sense to you that
$$vec a cdot (vec b + c) = vec a cdot vec b + c cdot vec a$$
neither side of the equation is defined, which means that you cannot use distribution the way it was used above.
edited 1 hour ago
answered 4 hours ago
Haris GusicHaris Gusic
1,142116
1,142116
$begingroup$
The RHS expression isn't defined either.
$endgroup$
– Hammerite
2 hours ago
$begingroup$
@Hammerite You are right. What a silly mistake. Thank you!
$endgroup$
– Haris Gusic
2 hours ago
add a comment |
$begingroup$
The RHS expression isn't defined either.
$endgroup$
– Hammerite
2 hours ago
$begingroup$
@Hammerite You are right. What a silly mistake. Thank you!
$endgroup$
– Haris Gusic
2 hours ago
$begingroup$
The RHS expression isn't defined either.
$endgroup$
– Hammerite
2 hours ago
$begingroup$
The RHS expression isn't defined either.
$endgroup$
– Hammerite
2 hours ago
$begingroup$
@Hammerite You are right. What a silly mistake. Thank you!
$endgroup$
– Haris Gusic
2 hours ago
$begingroup$
@Hammerite You are right. What a silly mistake. Thank you!
$endgroup$
– Haris Gusic
2 hours ago
add a comment |
ItIsLastThursday is a new contributor. Be nice, and check out our Code of Conduct.
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$begingroup$
This only makes sense if you make a vector space out of the base field
$endgroup$
– Brevan Ellefsen
1 hour ago