Q.No. 11 – 35 Carry One Mark EachWhich one of the following stat...
Eigenvalues of Real Symmetric Matrices
Real symmetric matrices have unique properties that make them an important topic in linear algebra. Among the options provided, the statement that all eigenvalues are real holds true for all real symmetric matrices.
Key Points about Real Symmetric Matrices:
- Real Eigenvalues:
- A fundamental theorem states that if a matrix is symmetric (i.e., it equals its transpose), then all its eigenvalues are guaranteed to be real numbers. This is a consequence of the Spectral Theorem.
- Positive Eigenvalues:
- While it's true that symmetric matrices can have positive eigenvalues, they can also have negative or zero eigenvalues. Therefore, this statement is not universally true.
- Distinct Eigenvalues:
- Symmetric matrices can have repeated eigenvalues. Thus, this statement does not hold for all real symmetric matrices.
- Sum of Eigenvalues:
- The sum of the eigenvalues equals the trace of the matrix, which is not necessarily zero for all matrices.
Conclusion
Thus, the only universally applicable statement for all real symmetric matrices is that all eigenvalues are real. This property is crucial in various applications, including stability analysis and quadratic forms, making it a foundational aspect of matrix theory.