Apps. and Interpretation for IBDP Maths Ebook 1 | Page 70

Your Practice Set – Applications and Interpretation for IBDP Mathematics
2. In an arithmetic sequence, u11 � 17 and S96 � 4512. Let u
1
and d be the first term and
the common difference of the arithmetic sequence respectively.
(a) (i) Write down the first equation connecting u
1
and d .
(ii) Write down the second equation connecting u
1
and d .
(b)
(iii) Hence, write down the values of u
1
and d .
Find u
n
in terms of n .
(c) Find the greatest value of n such that un
� 147 .
(d) Find u49 �u50 �u51 � �u95 � u96
.
(e) Find the value of n such that Sn
� 4949 .
[6]
[2]
[3]
[3]
[3]
3. In an arithmetic sequence, the general term is given by u �63� 3n, and the sum of the
first n terms is given by S
n
.
n
(a) (i) Write down the values of u
1
and u
2
.
(ii)
Hence, write down the common difference of the sequence.
(b) Find the smallest value of n such that un
�� 21.
(c) (i) Write down the values of S
1
.
[3]
[3]
(ii)
Find S
n
in terms of n .
(d) Find the value of n such that Sn
� 0 .
(e)
Find the value of
20
� ur
.
r�11
[3]
[3]
[3]
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