Your Practice Paper – Analysis and Approaches HL for IBDP Mathematics
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 )
4 .
( 1
|
n u )
1
� r
Sn
�
: The sum of the first n terms
1� r
|
5 . |
u1
S
: The sum to infinity , given that
�
1
1
1� r
|
9
Binomial Theorem
� Properties of the n factorial n !:
1 . n! � n�( n �1 ) �( n � 2 ) � �3�2�
1
2 . 0 ! � 1 3 . n! � n�( n � 1 )!
8
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