Chapter 4 - An Introduction to Functions - 4-7 Arithmetic Sequences - Practice and Problem-Solving Exercises - Page 279: 33

A(n) = A(n-1)-3 ; A(1) = 13

The formula for a recursive equation is A(n)=A(1-n)+c (c is the common difference) We can find c by subtracting the first and second terms from each other. c=13-10 c=3 This gives us the equation A(n)=A(n-1)-3 ; A(1)=13 And since we know the first term in the sequence, we have to list in next to the formula.