For n > 1, the maximum multiplicity of any eigenvalue of an n × n matrix with elements from R is
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GATE CSE 2026 Set 1 · Q13
Time
Select one answerSingle correct
Solution
Official answer: A) n
Linear AlgebraFor an matrix , the characteristic polynomial is of degree .
By the Fundamental Theorem of Algebra, a polynomial of degree has at most roots (counting multiplicities). Therefore, the algebraic multiplicity of any single eigenvalue can be at most .
For example, the identity matrix has a single eigenvalue with algebraic and geometric multiplicity equal to .
Hence, the maximum multiplicity is , which corresponds to Option (A).
Try the question first, then check your work.
Examiner trap
Consider the degree of the characteristic polynomial for an matrix, or look at the identity matrix .
This Linear Algebra previous year question is Q13 of the GATE CSE 2026 Set 1 paper. Find more GATE CSE PYQs on Linear Algebra in Engineering Mathematics, or browse all GATE CSE PYQs.
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Linear Algebra has 46 GATE CSE PYQs across 26 papers from 2011 to 2026. 13 of them are 1-mark MCQs like this one, and GATE CSE 2026 Set 1 has 2.
How GATE tests Linear AlgebraIndependent practice explanation verified by the GateAI team. GATE is conducted by the IITs; question text follows the official paper.