Page 215 - Math Smart - 7

Example 2

The term of a sequence is In = Sn + 7.

a) Find the first five terms of the sequence.
b) Find the difference between the 2"'' and the 5^^ terms of the sequence.
Solution

a) Ti=6x 1+7 = 6 + 7 = 13
12 = 6x2 + 7 = 12 + 7 = 19
13 = 6x3 + 7= 18+ 7 = 25
14 = 6x4 + 7 = 24 + 7 = 31
Is = 6x5 + 7 = 30+ 7 = 37

b) Difference between 2"^ and 5^^ terms = 15 -T2
= 37-19
= 18

Check My
Understanding

O For each number sequence,
a) write down the rule.
b) find the value of the term, In, and
c) find the 75'''term.

i) 2,4,6,8,...
ii) 2,4,8, 16, ...
iii) 3, 9, 27, 82,...
iv) 8, 16, 24, 32, ...
v) 8,64,512,4 096,...
vi) 10, 100, 1 000, 10 000, ...

O The m"'term of a sequence is In = 3rt-5. Find
a) the 3"* term.
b) the sum of the 3'^^ term and the 10'" term.

O The term is given. Use the term to find the first five terms of the sequence.
a) Tn = n + 3

1
b) Tn = 2« -
c) Tn= 11rt-9
d) Tn = 3«-3
e) Tn = 2« + 7
f) Tn = 4«-10