October November 2007 question 4 (iii) ONLY
The 1st term of an arithmetic progression is a and the common difference is d, where d ? 0.
(i) Write down expressions, in terms of a and d, for the 5th term and the 15th term. [1]
The 1st term, the 5th term and the 15th term of the arithmetic progression are the first three terms of
a geometric progression.
(ii) Show that 3a = 8d. [3]
(iii) Find the common ratio of the geometric progression. [2]
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Please include all ur steps and thankx in advance
