13-1

This past week in advanced math we took a test on chapter 11 and started chapter 13. On Thursday they learned section 13-1, but I was not there because I attended the volleyball game. On Friday when I came back I was kind of lost. I got the notes I missed and tried to teach myself section 13-1. It was kind of hard to understand so I will have to spend extra time on this chapter. Section 13-1 is about arithmetic and geometric sequences. Like the previous chapters it seems we use formulas. I tried doing the homework we were given over the weekend. I am going to try and work some example problems that I did understand.

Formulas:

Arithmetic – tn = t1 = (n – 1) d

Geometric – tn = t1 = r n-1

Examples:

Tell whether each sequence is arithmetic, geometric, or neither.

4n + 3 is arithmetic
It’s arithmetic because if you plug in the 4 terms you get 7, 11, 15, 19 and d = 4.

8 – 5n is geometric
It’s geometric because if you plug in the 4 terms you get 3, -2, -7, -12 and d = -5.

A sequence is usually neither if you plug in your terms and get a set of random numbers.