Question

13. The following series is arithmetic:

5+8+11+..+116
(a) Determine the number of terms in this series. Show how you arrived at your answer.

Answer 1

Explanation:

5+8+11+...+116x(n)=a+d(n-1) a=first term, d=common difference, n=term116=5+3(n-1)116=5+3n-3116=2+3n116-2=3n114=3nn=114/3n=38 terms S(n)=(n/2)(2a+[n-1]d)S(38)=(38/2)(10+37*3)S(38)=19(10+111)S(38)=19(121)S(38)=2299