Math Problem Statement

Let a linear map $T:R^2 -> R^3$ defined by $T\begin{pmatrix}2\1\end{pmatrix}=\begin{pmatrix}2\3\-3\end{pmatrix}$, $T\begin{pmatrix}1\2\end{pmatrix}=\begin{pmatrix}-2\4\0\end{pmatrix}$.

Then $T\begin{pmatrix}1\-4\end{pmatrix}$ is equal to a. $\begin{pmatrix}{r}0\4\end{pmatrix}$ b. $\begin{pmatrix}{r}0\4\end{pmatrix}$ c. $\begin{pmatrix}{r}0\4\end{pmatrix}$ d. $\begin{pmatrix}{r}2\0\2\end{pmatrix}$ e. $\begin{pmatrix}{r}2\0\2\end{pmatrix}$

Solution

To find T(14)T \begin{pmatrix} 1 \\ -4 \end{pmatrix}, we first need to determine the linear transformation TT based on the given information.

The linear map TT is defined by: T(21)=(233)T \begin{pmatrix} 2 \\ 1 \end{pmatrix} = \begin{pmatrix} 2 \\ 3 \\ -3 \end{pmatrix} T(12)=(240)T \begin{pmatrix} 1 \\ 2 \end{pmatrix} = \begin{pmatrix} -2 \\ 4 \\ 0 \end{pmatrix}

Any vector (xy)\begin{pmatrix} x \\ y \end{pmatrix} in R2\mathbb{R}^2 can be written as a linear combination of (21)\begin{pmatrix} 2 \\ 1 \end{pmatrix} and (12)\begin{pmatrix} 1 \\ 2 \end{pmatrix}. Thus: (xy)=a(21)+b(12)\begin{pmatrix} x \\ y \end{pmatrix} = a \begin{pmatrix} 2 \\ 1 \end{pmatrix} + b \begin{pmatrix} 1 \\ 2 \end{pmatrix}

We need to solve for aa and bb in the equation: (14)=a(21)+b(12)\begin{pmatrix} 1 \\ -4 \end{pmatrix} = a \begin{pmatrix} 2 \\ 1 \end{pmatrix} + b \begin{pmatrix} 1 \\ 2 \end{pmatrix}

This gives us the system of linear equations: 2a+b=1(1)2a + b = 1 \quad \text{(1)} a+2b=4(2)a + 2b = -4 \quad \text{(2)}

We can solve this system using substitution or elimination. Let's use elimination:

Multiply equation (1) by 2: 4a+2b=2(3)4a + 2b = 2 \quad \text{(3)}

Subtract equation (2) from equation (3): (4a+2b)(a+2b)=2(4)(4a + 2b) - (a + 2b) = 2 - (-4) 3a=63a = 6 a=2a = 2

Substitute a=2a = 2 into equation (1): 2(2)+b=12(2) + b = 1 4+b=14 + b = 1 b=3b = -3

Thus, we have a=2a = 2 and b=3b = -3. Therefore: (14)=2(21)3(12)\begin{pmatrix} 1 \\ -4 \end{pmatrix} = 2 \begin{pmatrix} 2 \\ 1 \end{pmatrix} - 3 \begin{pmatrix} 1 \\ 2 \end{pmatrix}

We now use the linearity of TT: T(14)=2T(21)3T(12)T \begin{pmatrix} 1 \\ -4 \end{pmatrix} = 2T \begin{pmatrix} 2 \\ 1 \end{pmatrix} - 3T \begin{pmatrix} 1 \\ 2 \end{pmatrix} =2(233)3(240)= 2 \begin{pmatrix} 2 \\ 3 \\ -3 \end{pmatrix} - 3 \begin{pmatrix} -2 \\ 4 \\ 0 \end{pmatrix} =(466)(6120)= \begin{pmatrix} 4 \\ 6 \\ -6 \end{pmatrix} - \begin{pmatrix} -6 \\ 12 \\ 0 \end{pmatrix} =(4+661260)= \begin{pmatrix} 4 + 6 \\ 6 - 12 \\ -6 - 0 \end{pmatrix} =(1066)= \begin{pmatrix} 10 \\ -6 \\ -6 \end{pmatrix}

Therefore, T(14)T \begin{pmatrix} 1 \\ -4 \end{pmatrix} is equal to (1066)\begin{pmatrix} 10 \\ -6 \\ -6 \end{pmatrix}.

None of the provided answer choices match (1066)\begin{pmatrix} 10 \\ -6 \\ -6 \end{pmatrix}, so it seems there may have been an error in the provided options.

Do you want more details or have any questions?

Here are five more questions you could ask:

  1. How do you find the kernel of a linear transformation?
  2. Can you explain how to compute the determinant of a 3x3 matrix?
  3. How do you solve a system of linear equations using matrix inversion?
  4. What is the significance of eigenvalues and eigenvectors in linear algebra?
  5. How do you determine if a set of vectors forms a basis for a vector space?

Tip: When solving systems of linear equations, it is often helpful to use matrix methods such as Gaussian elimination for efficiency and clarity.

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Math Problem Analysis

Mathematical Concepts

Linear Transformation
Matrix Operations
System of Linear Equations

Formulas

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Theorems

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Suitable Grade Level

Advanced High School