Things I need to remember about sequences and series:

Arithmetic

Terms:

• a=first term
• d=common difference
• Tn=general term (last term)
• n=number of terms
• Sn=sum of n terms

 _Formulas:

_Tn = T₁ + (n – 1)d

   or    

 

Geometric

Geometric sequence:

A list of numbers created by multiplying each term by a constant.

The “constant” is called the common ratio.

 

Terms:

• r=common ratio

 

Formula:

 

Vocabulary:

Finite: sequence that ends

Infinite: sequence that never ends

Convergent: terms that are getting closer together

Divergent: terms that are getting further apart