The 1st term of an arithmetic progression is and the common difference is , where .
(i) Write down expressions, in terms of and , for the 5th term and 15th term.
The 1st term, the 5th term and the 15th term of the arithmetic progression are the first terms of a geometric progression.
(ii) Show that .
(iii) Find the common ratio of the geometric progression.
(ii) Arithmetic Progression
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