Let e1= 1 0 and e2= 0 1 ​, y1= 4 5 ​, and y2= −2 7 ​, and let​ T: ℝ2→ℝ2 be a linear transformation that maps e1 into y1 and maps e2 into y2. Find the images of 4 −4 and

Respuesta :

Answer:

The image of [tex]\left[\begin{array}{c}4&-4\end{array}\right][/tex] through T is [tex]\left[\begin{array}{c}24&-8\end{array}\right][/tex]

Step-by-step explanation:

We know that [tex]T:[/tex] [tex]IR^{2}[/tex]  → [tex]IR^{2}[/tex] is a linear transformation that maps [tex]e_{1}[/tex] into [tex]y_{1}[/tex] ⇒

[tex]T(e_{1})=y_{1}[/tex]

And also maps [tex]e_{2}[/tex] into [tex]y_{2}[/tex]  ⇒

[tex]T(e_{2})=y_{2}[/tex]

We need to find the image of the vector [tex]\left[\begin{array}{c}4&-4\end{array}\right][/tex]

We know that exists a matrix A from [tex]IR^{2x2}[/tex] (because of how T was defined) such that :

[tex]T(x)=Ax[/tex] for all x ∈ [tex]IR^{2}[/tex]

We can find the matrix A by applying T to a base of the domain ([tex]IR^{2}[/tex]).

Notice that we have that data :

[tex]B_{IR^{2}}=[/tex] {[tex]e_{1},e_{2}[/tex]}

Being [tex]B_{IR^{2}}[/tex] the cannonic base of [tex]IR^{2}[/tex]

The following step is to put the images from the vectors of the base into the columns of the new matrix A :

[tex]T(\left[\begin{array}{c}1&0\end{array}\right])=\left[\begin{array}{c}4&5\end{array}\right][/tex]   (Data of the problem)

[tex]T(\left[\begin{array}{c}0&1\end{array}\right])=\left[\begin{array}{c}-2&7\end{array}\right][/tex]   (Data of the problem)

Writing the matrix A :

[tex]A=\left[\begin{array}{cc}4&-2\\5&7\\\end{array}\right][/tex]

Now with the matrix A we can find the image of [tex]\left[\begin{array}{c}4&-4\\\end{array}\right][/tex] such as :

[tex]T(x)=Ax[/tex] ⇒

[tex]T(\left[\begin{array}{c}4&-4\end{array}\right])=\left[\begin{array}{cc}4&-2\\5&7\\\end{array}\right]\left[\begin{array}{c}4&-4\end{array}\right]=\left[\begin{array}{c}24&-8\end{array}\right][/tex]

We found out that the image of [tex]\left[\begin{array}{c}4&-4\end{array}\right][/tex] through T is the vector [tex]\left[\begin{array}{c}24&-8\end{array}\right][/tex]

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