Is it possible to find matrix A satisfying certain conditions?

  • Thread starter Thread starter songoku
  • Start date Start date
  • Tags Tags
    Conditions Matrix
songoku
Messages
2,470
Reaction score
384
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
 
Physics news on Phys.org
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
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
Back
Top