-OR-

an=dn+c

similar to

y=mx+b

Using an= dn+c :

an= 5n+c

6 = 5(1)+c

c = 1

so an= 5n+1

and a100= 5(100)+1

= 501

Using an= dn+c :

an= 2n+c

14 = 2(1)+c

c = 12

so an= 2n+12

and a100= 2(13)+12

= 38

Using an= dn+c :

an= 2n+c

10 = 2(1)+c

c = 8

so an= 2n+8

a50= 2(50)+8 = 108

What are the first & last terms of this series?

How many terms are there in this series?

So our formula for the sum is:

Assignment: Section 7.2: problems 8-12, 14-16, 20-23, 29-37, 51-6

Section 7.4: problems 10-15, 17-26, 30-33, 36-38

(On all problems asking for recursive & explicit formulas, only give explicit

formula.)