Edexcel A2 C4 Mathematics June 2015 - Official Thread

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must meditate ...

I don't suppose you have a model answer from one one your worksheets to hand for a Q on volume of revolution about y axis where graph given parametrically? :hubba:

Reply 1041

Gilo98

Original post by studentwiz

how do you check to see if you have the right partial fraction?

combine partial fractions under a common denominator C3 style and check. Or sub x=1 for e.g. into both forms and see if you get the right answer. a little substitution can be used for nearly all C4 Qs to see if you are right

Reply 1042

raypalmer

Gold papers are edexcel p

Posted from TSR Mobile

Reply 1043

TeeEm

Original post by Gilo98

I don't suppose you have a model answer from one one your worksheets to hand for a Q on volume of revolution about y axis where graph given parametrically? :hubba:

I am truly ashamed ...

parametric
volume
about the y axis

3 aspects to be satisfied here ...
I did look the best is 2 aspects out of 3...
I will make one ...

Reply 1044

raypalmer

Past papers but jumbled up*******

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Reply 1045

studentwiz

Original post by Gilo98

thanks

Reply 1046

Gilo98

Original post by TeeEm

I am truly ashamed ...

parametric
volume
about the y axis

3 aspects to be satisfied here ...
I did look the best is 2 aspects out of 3...
I will make one ...

it is my life goal to find a flaw in your wealth of resources :wink:

Just a quick check though, would it simply be

[br][br]\pi\displaystyle\int x^2\frac{dy}{dt}\ dt[br][br]

Where limits are in terms of t and found using the values of y given in Q. apologies for poor formatting above, first time using LaTex

Be sure to quote me with the Q!!

Reply 1047

TeeEm

Original post by Gilo98

it is my life goal to find a flaw in your wealth of resources :wink:

Just a quick check though, would it simply be

[br][br]\pi\displaystyle\int x^2\frac{dy}{dt}\ dt[br][br]

Where limits are in terms of t and found using the values of y given in Q. apologies for poor formatting above, first time using LaTex

Be sure to quote me with the Q!!

it would be ...
(I even have revolution about the line x=4)

Reply 1048

Gilo98

Original post by TeeEm

it would be ...
(I even have revolution about the line x=4)

Thank you. Oooo, care to share with model answer? Got a feeling they might throw a horrid integration Q this year.

Reply 1049

studentwiz

how do you intergrate x/x^2-1

Reply 1050

TeeEm

Original post by Gilo98

Thank you. Oooo, care to share with model answer? Got a feeling they might throw a horrid integration Q this year.

can be done another way to the one I show ...

(edited 8 years ago)

;ulyktjh.pdf140.1KB

Reply 1051

anonwinner

Original post by studentwiz

how do you check to see if you have the right partial fraction?

Enter a random x value into the initial fraction and the partial fractions and see if you get the same result

Reply 1052

imnoteinstein

hows revision going guys? i absolutely suck at vectors, when they stray from the basics

could anyone explain how to go about Q8 e and f in June 14?

help

Original post by studentwiz

how do you intergrate x/x^2-1

You would state y= ln |x^2-1| then use chain rule to differentiate, obtaining dy/dx= 1/ln (x^2-1) *(2x) - 2x is the differential of the function. Then to make it equal to the form you want to times the integral by 1/a whichis 1/2. Therefore the integral would be 1/2ln|x^2-1| + C

Reply 1055

TeeEm

Original post by studentwiz

help

http://www.thestudentroom.co.uk/showthread.php?t=3327325

look at post 244, PDF 9/10 for similar types

Reply 1056

TeeEm

Original post by Gilo98

I don't suppose you have a model answer from one one your worksheets to hand for a Q on volume of revolution about y axis where graph given parametrically? :hubba:

question made.

Reply 1057

username1571649

I did really well in the June 14 paper, but I really dont understand this question?? Can someone help me on it