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Tricky method of differences FP2 question.

Exercise A Question 5.

Partial fractions = (2/r) + (1/(r+1)) - 3/(r+2)

Stuck on the second, I can't see the pattern.

Thanks guys.

Reply 1

Puddles the Monkey

Original post by Damien_Dalgaard

Exercise A Question 5.

Partial fractions = (2/r) + (1/(r+1)) - 3/(r+2)

Stuck on the second, I can't see the pattern.

Thanks guys.

Heya, I'm going to put this in the Maths forum for you as you should get more responses there.

You should also check out the forum to see if there's any other threads there which might be helpful to you!

http://www.thestudentroom.co.uk/forumdisplay.php?f=38

Reply 2

ghostwalker

Original post by Damien_Dalgaard

https://8fd9eafbb84fdb32c73d8e44d980d7008581d86e.googledrive.com/host/0B1ZiqBksUHNYTnpyeF8xQlZweHc/CH2.pdf

Exercise A Question 5.

Partial fractions = (2/r) + (1/(r+1)) - 3/(r+2)

Stuck on the second, I can't see the pattern.

Thanks guys.

Consecutive numerators are 2,1,-3, so stick them in a table (you'll have to imagine it having more columns/rows):

\begin{matrix} 2 & 1 & -3 & & & & \\ & 2 & 1 & -3 & & \\ & & 2 & 1 & -3 & \\ & & & 2 & 1 & -3\end{matrix}

And add the colums (these correspond to the same denominator).

Everything cancels, except two terms at the start, and two at the end.

Reply 3

Gome44

Original post by Damien_Dalgaard

Exercise A Question 5.

Partial fractions = (2/r) + (1/(r+1)) - 3/(r+2)

Stuck on the second, I can't see the pattern.

Thanks guys.

This is strange. I assume you're using the FP2 book by Keith Pledger. If so, this is my question 5 in the exercise ImageUploadedByStudent Room1424715708.016681.jpg

ImageUploadedByStudent Room1424715708.016681.jpg

Also, although this is probably not the best practise for fp2, the question says 'or otherwise' which means you could do it by induction

Reply 4

davros

Original post by Gome44

This is strange. I assume you're using the FP2 book by Keith Pledger. If so, this is my question 5 in the exercise ImageUploadedByStudent Room1424715708.016681.jpg

Also, although this is probably not the best practise for fp2, the question says 'or otherwise' which means you could do it by induction

The question the OP is tackling is contained in the pdf file attached to the original post. Strangely, it seems to be a SolutionBank with solutions to every question except the one the OP is doing!

Reply 5

Damien_Dalgaard

Original post by Gome44

This is strange. I assume you're using the FP2 book by Keith Pledger. If so, this is my question 5 in the exercise ImageUploadedByStudent Room1424715708.016681.jpg

Also, although this is probably not the best practise for fp2, the question says 'or otherwise' which means you could do it by induction

It is different to the book, it is on the solutionbank.

Original post by ghostwalker

Consecutive numerators are 2,1,-3, so stick them in a table (you'll have to imagine it having more columns/rows):

\begin{matrix} 2 & 1 & -3 & & & & \\ & 2 & 1 & -3 & & \\ & & 2 & 1 & -3 & \\ & & & 2 & 1 & -3\end{matrix}

And add the colums (these correspond to the same denominator).

Everything cancels, except two terms at the start, and two at the end.

Thank you so much, will have a go when I have finished some m2 regards!

Original post by davros

The question the OP is tackling is contained in the pdf file attached to the original post. Strangely, it seems to be a SolutionBank with solutions to every question except the one the OP is doing!