Question
upstudy study bank question image url

Compute the determinant using a cofactor expansion across the first row. Also compute the determinant by a cofactor expansion down the second column. \( \left|\begin{array}{rrr}2 & 0 & 3 \\ 2 & 4 & 3 \\ 0 & 4 & -1\end{array}\right| \) Compute the determinant using a cofactor expansion across the first row. Select the correct choice t ow and fill in the answer box to complete your choice. (Simplify your answer.) A. Using this expansion, the determinant is \( -(0)(-2)+(4)(-2)-(4)(0)=\square \) B. Using this expansion, the determinant is \( -(2)(-16)+(0)(-2)-(3)(8)=\square \) C. Using this expansion, the determinant is \( (0)(-2)-(4)(-2)+(4)(0)= \) (D. Using this expansion, the determinant is \( (2)(-16)-(0)(-2)+(3)(8)=-8 \). Compute the determinant using a cofactor expansion down the second column. Select the correct choice below and fill in the answer box to complete your choice. (Simplify your answer.) A. Using this expansion, the determinant is \( (2)(-16)-(0)(-2)+(3)(8)=\square \). B. Using this expansion, the determinant is \( -(\mathbb{1})(-2)+(4)(-2)-(4)(0)=\square \) C. Using this expansion, the determinant is \( -(2)(-16)+(0)(-2)-(3)(8)=\square \). O D. Using this expansion, the determinant is \( (0)(-2)-(4)(-2)+(4)(0)=\square \).

Ask by Simpson Mathis. in the United States
Mar 09,2025

Upstudy AI Solution

Tutor-Verified Answer

Answer

The determinant of the matrix is -8. **First Expansion (Across the First Row):** \[ \det(A) = (2)(-16) - (0)(-2) + (3)(8) = -8 \] **Second Expansion (Down the Second Column):** \[ \det(A) = (2)(-16) - (0)(-2) + (3)(8) = -8 \] Both methods yield the same determinant value of -8.

Solution

Sign in to Unlock Answers for Free!

A Learning Platform Trusted by Millions of Real Students and Teachers.

star-icon Unlock

Answered by UpStudy AI and reviewed by a Professional Tutor

Extra Insights

To compute the determinant of the matrix \[ \begin{pmatrix} 2 & 0 & 3 \\ 2 & 4 & 3 \\ 0 & 4 & -1 \end{pmatrix}, \] let's start with the cofactor expansion across the first row. 1. The first element in the first row is 2. Its minor, obtained by removing the first row and column, gives us the matrix \[ \begin{pmatrix} 4 & 3 \\ 4 & -1 \end{pmatrix}. \] The determinant of this \(2 \times 2\) matrix is \( (4)(-1) - (4)(3) = -4 - 12 = -16 \). Thus, the first term is \(2 \cdot (-16) = -32\). 2. The second element is 0, which will contribute 0 to the determinant. 3. The third element is 3. Its minor gives us \[ \begin{pmatrix} 2 & 4 \\ 0 & 4 \end{pmatrix}. \] The determinant of this matrix is \( (2)(4) - (4)(0) = 8\). Therefore, the contribution from this term is \(3 \cdot 8 = 24\). Adding these together (accounting for signs), we have: \[ -(2)(-16) + 0 + (3)(8) = -32 + 0 + 24 = -8. \] So, in answer form, we choose: **D. Using this expansion, the determinant is \( (2)(-16)-(0)(-2)+(3)(8)=-8 \).** Next, let's compute the determinant using a cofactor expansion down the second column. 1. The first element in the second column is 0, so it contributes 0. 2. The second element is 4. Its minor matrix is \[ \begin{pmatrix} 2 & 3 \\ 0 & -1 \end{pmatrix}. \] The determinant of this matrix is \( (2)(-1) - (3)(0) = -2 \). Thus, the contribution is \(4(-2) = -8\). 3. The third element is 4, which similarly has a minor matrix \[ \begin{pmatrix} 2 & 0 \\ 2 & 4 \end{pmatrix}, \] leading to a determinant of \( (2)(4)-(0)(2) = 8\), contributing \(4 \cdot 8 = 32\). So we sum these contributions: \[ 0 + 4 \cdot (-2) + (-4) \cdot 8 = 0 - 8 + -0 = -8. \] Thus, the answer is: **A. Using this expansion, the determinant is \( (2)(-16)-(0)(-2)+(3)(8)=-8 \).**

Related Questions

Latest Other Questions

Try Premium now!
Try Premium and ask Thoth AI unlimited math questions now!
Maybe later Go Premium
Study can be a real struggle
Why not UpStudy it?
Select your plan below
Premium

You can enjoy

Start now
  • Step-by-step explanations
  • 24/7 expert live tutors
  • Unlimited number of questions
  • No interruptions
  • Full access to Answer and Solution
  • Full Access to PDF Chat, UpStudy Chat, Browsing Chat
Basic

Totally free but limited

  • Limited Solution
Welcome to UpStudy!
Please sign in to continue the Thoth AI Chat journey
Continue with Email
Or continue with
By clicking “Sign in”, you agree to our Terms of Use & Privacy Policy