But wait â reconsider: âinvariant under \(90^\circ\) rotationâ means \( R\mathbfv = \mathbfv \), which we solved gives \( x = -y \) and \( x = y \Rightarrow x = 0, y = 0 \). So only trivial fixed vector. - AMAZONAWS 📅 March 6, 2026 👤 scraface Mar 06, 2026