[tex]k \pi - \pi^{2}\\k = \{0,\pi, 2\pi, 3\pi,...\}[/tex]
[tex]dla \ \ k = 0\\k\pi^{2}-\pi^{2} = 0\cdot\pi^{2}-\pi^{2} = \underline{-\pi^{2}}\\\\dla \ \ k=\pi\\k\pi-\pi^{2} =\pi\cdot \pi-\pi^{2} = \pi^{2}-\pi^{2} = \underline{0}\\\\dla \ \ k = 2\pi\\k\pi-\pi^{2} = 2\pi\cdot \pi - \pi^{2} = 2\pi^{2}-\pi^{2} = \underline{\pi^{2}}\\\\dla \ \ k = 3\pi\\k\pi-\pi^{2} = 3\pi\cdot \pi - \pi^{2} = 3\pi^{2}-\pi^{2} = \underline{2\pi^{2}}\\\\\underline{\{-\pi^{2}, 0, \pi^{2}, 2\pi^{2}, ...\}}[/tex]
