There are six symmetries of an equilateral triangle: three reflections, and three rotations (thinking of the identity as one the rotations).
Label the three reflections \(s_1\), \(s_2\) and \(s_3\). Label the identity by \(e\), rotation by \(120^{\circ}\) as \(r_1\), and rotation by \(240^{\circ}\) clockwise as \(r_2\).
What are the inverses of \(r_1\) and \(s_1\)?