Edexcel C3,C4 June 2013 Thread

Reply 2540

Anonymous1717

Does anyone's calculator have the ability to calculate the modulus of something? (Graphic or normal)

Reply 2541

wndms

1

Original post by Anonymous1717

Does anyone's calculator have the ability to calculate the modulus of something? (Graphic or normal)

Yeah the normal casio one can do it

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Reply 2542

yaboy

Original post by ChelseaSam

C4: How do you integrate cot2x? Formula book states that the integral of cotx is ln|sinx| so would it be... 0.5ln|sin2x|?

well the book says you dont need to know how to do it.

But I did this, using recognition you can spot that cos2x/sin2x = cot2x

differentiate six2x you get 0.5cos2x so in other words it follows the rule f '(x)/f(x)= ln(f(x))

just take the 0.5 out the integral sign and you end up with 0.5ln|Sin2x|

Reply 2543

Baraf

8

what is the derivative of cos(x^2) ?

Reply 2544

m4ths/maths247

7

Original post by Baraf

what is the derivative of cos(x^2) ?

Chain rule
Let u = x^2
y = cosu

go from there (assuming you don't want to do the 'mental' method of differentiate the outside function, rewrite the inside function and multiply through by the derivative of the inside function)

Reply 2545

Anonymous1717

Original post by wndms

Yeah the normal casio one can do it

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I have a Casio and a Sharp - what does the button look like?!
Thanks :smile:

Reply 2546

Zzzyax

2

perhaps someone can help me please intergrate: 1/(X^2+1) dx, is this possible in c4

what about (sin(x)+1)^4 , using chain rule, can you do that,(without exapanding!) ?

Reply 2547

Anonymous1717

Solomon paper D, C3 - the very last question is about iteration and they go up to x5 in the mark scheme, even though the question doesn't specify (the question just asks to find the value to 3sf). Is it just because if you keep pressing =, after x5 the value doesn't change to 3sf?
Would really appreciate any answers.
http://www.school-portal.co.uk/GroupDownloadFile.asp?GroupId=1152244&ResourceId=3992023

Reply 2548

JenniS

2

Original post by Anonymous1717

Solomon paper D, C3 - the very last question is about iteration and they go up to x5 in the mark scheme, even though the question doesn't specify (the question just asks to find the value to 3sf). Is it just because if you keep pressing =, after x5 the value doesn't change to 3sf?
Would really appreciate any answers.
http://www.school-portal.co.uk/GroupDownloadFile.asp?GroupId=1152244&ResourceId=3992023

pretty sure its just that

Reply 2549

Baraf

8

Original post by m4ths/maths247

Chain rule
Let u = x^2
y = cosu

go from there (assuming you don't want to do the 'mental' method of differentiate the outside function, rewrite the inside function and multiply through by the derivative of the inside function)

-2xsin(x^2) ?

Reply 2550

The Guide.

How's everyone feeling about Thursday? You guys prepared??

Reply 2551

m4ths/maths247

7

Original post by Baraf

-2xsin(x^2) ?

yes

Reply 2552

DenchKing1832

How many past papers has everyone done? I've done 16 in 6 days and am hitting around 73/75 or above consistently

Reply 2553

The Guide.

Original post by DenchKing1832

How many past papers has everyone done? I've done 16 in 6 days and am hitting around 73/75 or above consistently

Done all for C3 consistently been getting 72 to 74 out of 75. C4 done most of the papers but been getting 66 to 70 out of 75... Kinda getting worried for C4 need to cut out the silly mistakes.

Reply 2554

Cosine

Original post by The Guide.

How's everyone feeling about Thursday? You guys prepared??

I think I'll be okay with C3 by Thursday, it's C4 I'm more worried about next week!! And don't even remind me of FP2 next week too D:

Reply 2555

The Guide.

Original post by Cosine

I think I'll be okay with C3 by Thursday, it's C4 I'm more worried about next week!! And don't even remind me of FP2 next week too D:

God willing I'll be okay with C3 for Thursday. I hope the function questions will be kind :smile:

Reply 2556

Poffertje

9

Can someone please explain how to differentiate 2ln(x/3)
I can't seem to get the right answer!
Its probably something simple but I'm just missing it.
Thank you!

Reply 2557

PoorLoser

2

how would you integrate sec(^2)xtan(^2)x ?

In the answer they "assumed" y=tan cubed x
but how would you check this by differentiating? how do you differentiate tan cubed x???

thanks!!! (this is for c4 btw!) any help appreciated!

Reply 2558

Zaid-Khatib

What is the best way to study for c3
is it okay if i did mixed exercises for the first 5 chapters.
chapters and 7 the trigonometry ones, i only did examples and a couple of exercises.
The last chapter the differentiation chapter i did everything in it
it's time to do the past papers.
Is it okay if i only did examples in chapters 6 and 7 ?

Reply 2559

gshock

6

Original post by Myda

Can someone please explain how to differentiate 2ln(x/3)
I can't seem to get the right answer!
Its probably something simple but I'm just missing it.
Thank you!

Lula what you do first is differentiate ln(x/3) which is 1/3 multiplied by 1 over x/3 which gives you 1/3 multiplied by x/3 (x/3 is the differential of ln bit) and then multiply by 2 which is overall 2 x 1/x which makes 2/x there you go enjoy and good luck ! :colondollar:

Edexcel C3,C4 June 2013 Thread

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