SEQUENCE

• Arithmetic

  (+,-)

  has a comman difference (d)

  d= a2-a1

  a1= (n-1)+d

  middle= a+b/2

  Series: sum of all

  Sn= n(a1=an)/2

  sn= n/2 (2a1+(n-1)d)
• GEOMETRIC SEQUENCE

  (x, division)

  has common ratio

  r= a2/a1

  an= a1r^n-1

  SERIES;

  finite

  sn= a1(1-r^n)/1-r

  Infinite

  sn= a1/1-r