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QuestionMathematics

How do you find the discriminant for a 2×2 matrix?
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Answer

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Step 1:
I'll solve this step-by-step, using precise LaTeX formatting:

Step 2:
: Understanding the Discriminant

\Delta = ad - bc
The discriminant for a 2×2 matrix is a scalar value that provides important information about the matrix's characteristics.

Step 3:
: Breaking Down the Components

- $$d$$ is the element in the second row, second column
- b is the element in the first row, second column

Step 4:
: Calculation Method

To find the discriminant:

Step 5:

Multiply the elements on the main diagonal ($$a$$ and $$d$$)

Step 6:

Multiply the elements on the other diagonal ($$b$$ and $$c$$)

Step 7:

Subtract the second product from the first product

Step 8:
: Significance of the Discriminant

- If $$\Delta < 0$$, the matrix has complex conjugate eigenvalues
- If \Delta = 0, the matrix has repeated eigenvalues

Final Answer

The discriminant of a 2×2 matrix A = \begin{pmatrix} a & b \ c & d \end{pmatrix} is calculated as \Delta = ad - bc.