Edexcel C3,C4 June 2013 Thread

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Help needed with integration! please give me the steps on integrating this. tan(2x - π/6) with lower limit 0 and upper limit π/12. how can i get the answer 1/4 ln3.

Reply 4001

Chris-69

When differentiating y = 2^x x 4^x, I get 2^2x(3ln2), yet the book says the answer is 2^3x(3ln2).

Can anyone explain how to get the right answer?

(edited 10 years ago)

Reply 4002

Kreayshawn

can they ever ask us to rotate something more/less than 2pi radians? any examples of questions or explanations on what they would ask and how to go about it?

Original post by TeddyBasherz

Does anyone have a link to the jan 2013 c4 paper? The booklet version not the version on examsolutions? Thanks

http://eiewebvip.edexcel.org.uk/Reports/Confidential Documents/1301/6666_01_rms_20130307.pdf

Reply 4003

task

hi how do I integrate ImageUploadedByStudent Room1371405121.475193.jpg

thanks

ps that is 2^2-2x -1

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(edited 10 years ago)

Reply 4004

otrivine

Original post by task

hi how do I integrate ImageUploadedByStudent Room1371405121.475193.jpg

thanks

ps that is 2^2-2x -1

Posted from TSR Mobile

have you tried using sub method? so assume u=2-2x ?

Reply 4005

TDL

Original post by task

hi how do I integrate ImageUploadedByStudent Room1371405121.475193.jpg

thanks

ps that is 2^2-2x -1

Posted from TSR Mobile

rewrite as

4(2^{-2x})

and should be simple from there

Reply 4006

task

Original post by otrivine

have you tried using sub method? so assume u=2-2x ?

no I haven't ill give that a go now, thanks
didn't even think of that oops

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Reply 4007

otrivine

Original post by TDL

rewrite as

4(2^{-2x})

and should be simple from there

do you think if you use a sub method? is okay

Reply 4008

task

Original post by TDL

rewrite as

4(2^{-2x})

and should be simple from there

sorry could you explain how you got that?

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Reply 4009

physicso

Does anyone know how to integrate 2^x???? Is it always 2^x/ln2? (say: if y=4.5^t does the integral = 4.5^t/ln4.5)?

Reply 4010

otrivine

http://www.examsolutions.net/a-level-maths-papers/worked-solution/worked-solution.php?paper_id=41&solution=4.4

why and where did he get the 2 from?

Reply 4011

verel

where can i get past replacement papers? :s-smilie:

Original post by task

sorry could you explain how you got that?

Posted from TSR Mobile

sure

2^{2-2x} = 2^2 \times 2^{-2x} = 4 \times 2^{-2x}

full solution

Spoiler

hope this helps

Reply 4014

TDL

Original post by ITomI

u = cosx

Reply 4015

otrivine

Original post by task

no I haven't ill give that a go now, thanks
didn't even think of that oops

Posted from TSR Mobile

did it work with sub method??

Reply 4016

LastOfUs

Original post by silentriver

Help needed with integration! please give me the steps on integrating this. tan(2x - π/6) with lower limit 0 and upper limit π/12. how can i get the answer 1/4 ln3.

I think your answer is wrong btw. I checked on my calculator and got 1/2 ln(root3/2). Anyway, I wrote it as the integral of sin(2x-pi/6)/cos(2x-pi/6), and then manipulated it to get it in the form: integral of f'(x)/f(x). You'll get an ln function for your result, and then sub your limits.