| Exam Board | Edexcel |
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| Module | C12 (Core Mathematics 1 & 2) |
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| Year | 2014 |
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| Session | June |
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| Topic | Arithmetic Sequences and Series |
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9. (i) Find the value of \(\sum _ { r = 1 } ^ { 20 } ( 3 + 5 r )\)
(ii) Given that \(\sum _ { r = 0 } ^ { \infty } \frac { a } { 4 ^ { r } } = 16\), find the value of the constant \(a\).