Notes
Arithmetic_Mixed_Problems (Practice Exercises)
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Formula:
Arithmetic Sequence
The nth term of an arithmetic sequence:
Un = U1 + (n - 1) d
The sum of n terms of an arithmetic sequence:
Sn = n/2 (2 U1 + (n - 1) d)
Sn = n/2 (U1 + Un)
The first term of an arithmetic sequence is -8 and the common difference is 3.
(a) Find the seventh term of the sequence.
(b) The last term is 100. How many terms are there?
U1 = -8
d = 3
Un = 100
(a) Un = U1 + (n - 1) d
U7 = -8 + (7 - 1) 3
U7 = 10
(b) Un = U1 + (n - 1) d
100 = -8 + (n - 1) 3
100 = -8 + 3n - 3
100 = -11 + 3n
111 = 3n
n = 37
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- Grade 11 Mathematics Note on Arithmetic_Mixed_Problems (Practice Exercises) , created by ST Hiu Cheung on 22/10/2017.
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