Year 12s: what will be the first way you research your future options? >>

FP2 Finite series

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It may not be their answer but it is correct. It is easy to show that their answer is wrong.

For your next question, the sum required is 4r^3+2r. You have r^3 from the last part and the sum for r is standard.

Yeah, i've solved them both now. I did mention that I thought the answer for the first one was incorrect. It's a little disheartening to be studying on your own and to then find out the answers in the exam-board-issued text book are wrong. But, such is life!

Anyways, thanks for everyone's help. I will no doubt be back for more in the near future :smile: