. Prove that there are no integers n with o(n) = n/13 %3D

(3a) Let n E Z. Prove that if 3 ł n, then 3|(n² – 1)

Prove Γ (n) = (n-1)! where n ∈ ℕ

Consider these four statements: A: 3 + 3+...+ n? for every integer n>1. 1 1.2 2.3 n(n+1) n+1' B: 1+2+ 22+...+2" 27+1 – 1, for every integer n > 0. %3D C: (1 - ) (1 – ) (1 – †).. (1 – ±) =i, for every integer n > 2. D: 2+4+6+...+2n = n² +n, for every integer n > 1. Only B and C are true. Only A, C, and D are true. O Only B, C, and D are true. O Only C and D are true. O A, B, C, and D are true. O Only B and D are true.