An arithmetic series is defined by its first term p p\,p and its common difference qqq.
Prove that the sum of the first n n\,n terms of this series is
12n[2p+(n−1)q] \frac{1}{2}n[2p + (n-1)q] 21n[2p+(n−1)q]63 exam-style questions on CCEA A Level Maths 3.3.4 Sequences and series (A-level only). Each one has a worked solution and a mark scheme showing where the marks go.