Originally Posted by
antman
How do I prove / disprove "If a Matrix A is nonsingular, then the homogeneous system Ax=0 has a nontrivial solution?"
I know that if A is nonsingular, then $\displaystyle A^{-1} $exists and multiplying both sides of Ax=0 by $\displaystyle A^{-1}$ gives $\displaystyle A^{-1}(Ax)=A^{-1}(0)$ so $\displaystyle ({\color{red}A^{-1}A})(x)=0$ then $\displaystyle (I_n)x=0$ and x=0. Therefore, the only solution to Ax=0 is x=0 so a nonsingular matrix never has a nontrivial solution to Ax=0.
Is this enough to disprove the statement?