7
Arithmetic Sequences
� Properties of an arithmetic sequence u n
:
1 . u
1
: First term 2 . d � u2 �u1 � un
� un
� 1: Common difference 3 . u � u1 � ( n � 1 ) d : General term ( n th term ) n n n
�
1� � �
1� : The sum of the first n n terms
2 2
4 . S �2 u ( n 1 ) d� �u u � n
� |
n
� ur � u1
� u2
� u3
�
|
� un�
1
� un
|
|
r�1 |
|
: Summation sign
8
Geometric Sequences
� Properties of a geometric sequence u n
:
1 . u
1
: First term 2 . r � u2 �u1 � un
� un
� 1
: Common ratio
3 . u u r �
n 1 n
�
1
� : General term ( n th term )
1
4 . ( 1 n
u � r S ) n
� : The sum of the first n terms 1� r
9
Financial Mathematics
� Compound Interest :
PV : Present value r %: Interest rate per annum ( per year ) n : Number of years k : Number of compounded periods in one year kn
� r � FV �PV
�1�
� : Future value � 100 k �
I �FV � PV : Interest
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