Consider the process of inserting three numbers between two unequal real numbers p and q so that the five numbers in order form an arithmetic progression.
(i) State the general term an of an arithmetic progression whose first term is a and common difference is d.
(ii) Show that, for the progression described above, the common difference equals 4q−p.
(iii) Using the result of part (ii), determine the three numbers that must be inserted between 2 and 14 to obtain an arithmetic progression.