1/7/09 Keegan

We started class with the warm up involving writing terms, using recursive definitions and using sigma notation. We went over that when writing a recursive definition make sure you have two parts. The first part is you must say what equals, then the second part is to say what equals. We also discussed that when using sigma notation, if you are struggling to find the upper limit just use algebra. Set your equation equal to the final term given, and sub in X as the unknown. X will then turn out to be the upper limit in the sigma notation.

We then went over the homework. We talked about methods for finding the equations of a sequence. We talked about looking for patterns such as if you come out with differences of the differences. This means the equation will usually be exponential. As we move forward in this unit, a lot of the same patterns will come up frequently.

We then began to take notes on arithmetic sequences
The definition of an arithmetic sequence:

= +d
where d is called the common difference
We then went over several examples using this definition.

The nth term of an arithmetic sequences is
= d * n +
or
= + d (n-1)

The sub formula is:
= /2( + )

homework for next class:
P. 659/ 1,9,11,16,19,21,27,37,39,41,45,67,69,71,85



next scribe Angus