Let R be a rotation and S be a reflection of the euclidean plane I Give a precise deion of RS, relating it to the classification of isometries of E². Be careful of special cases. (iii) In the quaternions H, what is the order of the group Go generated by i and j? Describe the image G₁ of Go under the homomorphism Sp(1)→ SO(3). Is Go the rotational symmetry group of any of the platonic solids?