We now consider the set S of all students enrolled in this section of eecs2001. There are 150 students enrolled. (You dont need to know their names or student IDs to answer this question.)

Below we define two relations R₁ and R₂ on the set S ={ s₁, s₂, s₃, . . . , s₁₅₀ }. For both relations determine whether it is an equivalence relation and explain why or why not.

• For the first relation R₁, we define two students s_i and s_j to be related and write s_i R₁s_j if their sets A have the same size. A = {n₁, n₂, . . . , n₉}
• For the second relation R₂, we define two students s_i and s_j to be related and write s_i R₂ s_j if they have taken at least 4 different classes together.