Edexcel C1 — Question 6

Exam BoardEdexcel
ModuleC1 (Core Mathematics 1)
TopicArithmetic Sequences and Series

  1. (a) Evaluate
$$\sum _ { r = 1 } ^ { 50 } ( 80 - 3 r )$$ (b) Show that $$\sum _ { r = 1 } ^ { n } \frac { r + 3 } { 2 } = k n ( n + 7 )$$ where \(k\) is a rational constant to be found.