Linear Algebra and Its Applications · Problem 1.2.11

Matrices and Gaussian Elimination — Gilbert Strang

Mathematics · geometry-of-linear-equations

Problem

These equations are certain to have the solution

x = y = 0

. For which values of

a

is there a whole line of solutions?

\begin{aligned} ax + 2y &= 0 \\ 2x + ay &= 0 \end{aligned}