The first three terms of a geometric series are (k+4)(k + 4)(k+4), k k\,k and (2k−15)(2k - 15)(2k−15) respectively, where k k\,k is a positive constant.
Show that k2−7k−60=0k^2 - 7k - 60 = 0k2−7k−60=0.
Hence show that k=12k = 12k=12.
Find the common ratio of this series.
Find the sum to infinity of this series.
9 exam-style questions on Edexcel A Level Old Maths Sequences and Series. Each one has a worked solution and a mark scheme showing where the marks go.