The first three terms of a geometric series are (2k+2)(2k+2)(2k+2), (k+4)(k+4)(k+4), and k k\,k respectively, where k k\,k is a positive constant.
Show that k2−6k−16=0k^2 - 6k - 16 = 0k2−6k−16=0.
Hence show that k=8k = 8k=8.
Find the common ratio.
Find the sum to infinity of the series.
16 exam-style questions on OCR (MEI) A Level Maths 1.6.16 Sum to infinity of a geometric series (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.