The Student Room Group
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>
Competition - post a photo you've taken of nature >>

FP1 Series Help

image.jpg
Hi I would need help with part 2 of this question, my answer looks quite unrealistic
Thanks 🙏🏼
Reply 1
Avatar for Zacken
Zacken
22
Original post by Amarante
Hi I would need help with part 2 of this question, my answer looks quite unrealistic
Thanks 🙏🏼


Well, what's your answer? What did you do? Show us.
Reply 2
Avatar for Amarante
Amarante
OP
8
Original post by Zacken
Well, what's your answer? What did you do? Show us.

image.jpg

As I said, looks unrealistic, I can't spot the mistake and I'm not sure if the application of the formula is correct when r is denominator
Original post by Amarante


As I said, looks unrealistic, I can't spot the mistake and I'm not sure if the application of the formula is correct when r is denominator


That's not right. You should apply the method of differences for ∑r=1n1r−1r+1\displaystyle \sum_{r=1}^n \frac{1}{r} - \frac{1}{r+1}
you cannot apply the formula for summation of x if it says 1/x
instead put in numbers and see how the terms cancel.
Reply 5
Avatar for Amarante
Amarante
OP
8
Original post by the bear
you cannot apply the formula for summation of x if it says 1/x
instead put in numbers and see how the terms cancel.

I'm lost, do I just substitute n when r is denominator?
you start off with r = 1, then 2, then 3, then 4, then 5,... then go to the end where r is n -1 , and finally n.

you should look for a pattern of cancellations.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you