Exercise. Which of the following sequences are arithmetic sequences for n = 1, 2, 3, ...? an = -3n + 5 an = -5. 7 +4 an = 5 an = (3) . an-1 where al = 10 an = An2+n-14 n+2 an = 2n. cos(2An+ TT) ) an = COS(7 / 2n ) an = COs ( Trn - 5) an = n . cos (2Tn) + 4 ? Check work