Edexcel FP1 — Question 14

Exam BoardEdexcel
ModuleFP1 (Further Pure Mathematics 1)
TopicProof by induction

14. $$f ( n ) = ( 2 n + 1 ) 7 ^ { n } - 1$$ Prove by induction that, for all positive integers \(n , f ( n )\) is divisible by 4 .