Finding a Partial Sum of an Arithmetic Sequence In Exercises 65-10, find the indicated nth partial sum of the arithmetic sequence. / 65. 8, 20, 32, 44, . . . n = 10 66. 2, 8, 14, 20, . . ., n = 25In Writing Terms of an Arithmetic Sequence In Exercises ce is 39-42, write the first five terms of the arithmetic sequence. Find the common difference and write the nth term of the sequence as a function of n. 39. a = 15, ak+1 = ak + 4 0002 1000 Of8 40. a = 6, ak+1 = ax + 5 000,208 9. 3.7, 4., 41. a1 = 5, ak+1 =- 10 - In + ak Writing the Terms of a Sequence In Exercises 11-20, 42. a = 1.5, ak+1 = ak - 2.5 write the first five terms of the sequence. Determine whether or not the sequence is arithmetic. If it is, find the common difference. (Assume n begins with 1.) two 11. a = 8 + 13n 12. a, = 2" + n 1 to Veri 13. an = n + 1 14. a = 1 + (n - 1)4 15. a, = 150 - 7n