Proving Linearity of L:R(4)→R(4)

  • Thread starter jlucas134
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In summary, the linear operator is defined by L(u+v)=(this is what I get) and is represented by (a b c d)^T.
  • #1
jlucas134
22
0
I need some help solving this...not even sure how to start...

Let L:R(4) goes to R(4) be the linear transformation defined by
-matlab notation, the value is a 4x1 column
L ( [ a b c d])=[ a-b
0
c-d
0 ]


Show directly L is linear.
 
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  • #2
In order to get help, you should show some efforts.

What is the definition of a linear operator?
 
  • #3
All I can say is "Just do it!"

Write down the requirements for a linear transformation, insert your L, and do the calculations!
 
  • #4
Alright...

I am still trying to figure out this message board...
I forgot to include what I already know...

I know you have to prove that L(u+v)=L(u)+ L(v) and L(c*u)=c*L(u), but I don't understand how to set it up.

I tried to separate it into a1 and a2, but just get confused...

Do I have to place it in the standard matrix representation then solve?
 
  • #5
still working with it...
if I set u=a1, b1, c1, d1 and v=a1, b1, c1, d1
set L(u+v)=(this is what I get)

[ (a1+a2)-(b1+b2)
0
(c1+c2)-(d1+d2)
0 ]

which equals L(u)+L(v)

for L(c*u)=c*L(u)

[c(a-b) c*0 c(c-d) c*0]
which converts to c[a-b 0 c-d 0] which breaks down to c*L(u)


Is the close?
 
Last edited:
  • #6
That's exactly it.

(except that you said " I set u=a1, b1, c1, d1 and v=a1, b1, c1, d1" when you mean "I set u=a1, b1, c1, d1 and v=a2, b2, c2, d2". Doesn't your class or textbook have some convention for writing vectors- say (a, b, c, d) or <a, b, c, d> rather than just a, b, c, d which can be confusing?
 
  • #7
ok...think i get it

When I first did it, it didn't look right...almost too simple to be correct. Thanks for correcting me with my notation.

my text does have a format but this doesn't support the large brackets required for a 4X1 matrix.

I will try to make the matrix a little more easier to read...

Would the notation for MATLAB entry suffice?
 
  • #8
jlucas134 said:
my text does have a format but this doesn't support the large brackets required for a 4X1 matrix.

You can always write (a b c d)^T to represent a 4x1 matrix of you want.
 
  • #9
Check me

Can someone verify my signs are correct for when I solved, with help from the board?
 

1. What is the definition of linearity in the context of L:R(4)→R(4)?

Linearity in the context of L:R(4)→R(4) means that the mapping or transformation between the vector space R(4) and itself preserves the properties of a linear transformation. This means that the transformation must satisfy the properties of additivity and scalar multiplication.

2. What are the properties of a linear transformation?

The properties of a linear transformation are additivity and homogeneity. Additivity means that the transformation must satisfy the property of f(x+y) = f(x) + f(y), where x and y are vectors in the vector space. Homogeneity means that the transformation must satisfy the property of f(cx) = cf(x), where c is a scalar and x is a vector in the vector space.

3. How do you prove the linearity of L:R(4)→R(4)?

To prove the linearity of L:R(4)→R(4), you must show that the transformation satisfies the properties of additivity and homogeneity. This can be done by applying the transformation to two vectors, x and y, and showing that the resulting transformed vectors, L(x) and L(y), satisfy the properties of additivity and homogeneity.

4. Can a non-linear transformation exist in L:R(4)→R(4)?

No, a non-linear transformation cannot exist in L:R(4)→R(4). This is because the mapping between the vector space R(4) and itself must preserve the properties of a linear transformation, as stated in the definition of linearity. Any transformation that does not satisfy the properties of additivity and homogeneity is considered non-linear.

5. Why is it important to prove the linearity of L:R(4)→R(4)?

Proving the linearity of L:R(4)→R(4) is important because it ensures that the mapping or transformation between the vector space and itself is valid and reliable. It also allows for the use of mathematical techniques and tools that are specific to linear transformations, which can aid in solving problems and analyzing data in various scientific fields.

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