Is it possible to find matrix A satisfying certain conditions?

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SUMMARY

The discussion centers on the existence of a matrix A that satisfies specific conditions regarding the rank of the matrix and its transpose. It is established that if the equation Ax = b has no solution, then the rank of A must be less than m. Conversely, if the equation A^T y = c has exactly one solution, the rank of A^T must equal m. Since the ranks of A and A^T cannot be equal under these conditions, it is concluded that such a matrix A cannot exist.

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Homework Statement
Is it possible to find A being a m by n matrix, and two vectors b and c, such that Ax = b has no solution and ##A^T## y = c has exactly one solution? Explain why.
Relevant Equations
Maybe Rank
Since Ax = b has no solution, this means rank (A) < m.

Since ##A^T y=c## has exactly one solution, this means rank (##A^T##) = m

Since rank (A) ##\neq## rank (##A^T##) so matrix A can not exist. Is this valid reasoning?

Thanks
 
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songoku said:
Homework Statement: Is it possible to find A being a m by n matrix, and two vectors b and c, such that Ax = b has no solution and ##A^T## y = c has exactly one solution? Explain why.
Relevant Equations: Maybe Rank

Since Ax = b has no solution, this means rank (A) < m.

Since ##A^T y=c## has exactly one solution, this means rank (##A^T##) = m

Since rank (A) ##\neq## rank (##A^T##) so matrix A can not exist. Is this valid reasoning?

Thanks
Looks ok to me.
 
Thank you very much fresh_42
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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