Equivalent statements to matrix A is orthogonal

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SUMMARY

A matrix A is orthogonal if and only if its inverse A^{-1} equals its transpose A^{T}, which leads to the conclusion that AA^{T} equals the identity matrix I. The discussion raises the question of whether the statement A is orthogonal is equivalent to A^{2} equals I. The consensus is that these two statements are not equivalent, as demonstrated by manipulating the equation A^{2} = I using A^{-1} to explore the relationship between the two conditions.

PREREQUISITES
  • Understanding of matrix operations, specifically matrix multiplication and transposition.
  • Familiarity with the concept of matrix inverses and identity matrices.
  • Knowledge of orthogonal matrices and their properties.
  • Basic algebraic manipulation skills to analyze matrix equations.
NEXT STEPS
  • Study the properties of orthogonal matrices in linear algebra.
  • Learn about the implications of A^{2} = I in the context of matrix theory.
  • Explore the relationship between matrix inverses and transposes in more depth.
  • Investigate examples of orthogonal matrices and their applications in various fields.
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Students and professionals in mathematics, particularly those studying linear algebra, as well as anyone involved in fields that utilize matrix theory, such as computer graphics and data science.

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A is orthogonal if the A^{-1} = A^{T}.

Thus, AA^{T} = I.

However, is the statement A is orthogonal equivalent to A^{2}=I.

I don't think the statements are equivalent, but it comes from a test. Thus, I'd hope the test is correct.
 
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Multiply both sides of the A^2=I expression by A^-1 and see what you get.

From that expression you will be able to see the relationship required for both to be true.
 

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