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Edexcel C3,C4 June 2013 Thread

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Can anyone recommend when I should finish the C4 Papers Please?

Physics and Chemistry are taking up alot of time. I'm up to 2012 on the C3 Papers, my results thus far are pretty decent......

Would Starting the real C4 papers on Thursday be leaving it too late?

Have you done a good amount of practice for C4 yet, like Solomons and stuff? If so, starting the real C4 on Thursday should be fine, imo.

Reply 2221

Tchombo

Original post by AHarris

ImageUploadedByStudent Room1370592426.104513.jpg

Can anyone do part d of q15
The answer in the back is wrong but I still have no idea how to get an answer :/

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I rushed this but it's about finding limits for theta and multiplying the "y" expression by dx/d(theta) to integrate wrt theta I think

IMG_7999.JPG58.8KB

Reply 2222

bestfriends33

For C3 trig questions (finding x)..
When im at the stage where for example: cos(2x-36.87) = 2/5
I normally write: let 2x-36.87 =b and then continue my working with cosb =2/5 as I find this easier.. Then convert it back later.

When doing this I normally just find lots of values by adding and subtracting 360.. However can someone please tell me how to change the range so that I know when to stop e.g. if it was 0 < x < 180 what would it become when I let 2x-36.87 =b?

Thanks :smile:

Reply 2223

Tchombo

Original post by bestfriends33

if 0 < x < 90 , -12 < B < 78 where B=x-12, you put the range boundaries in for x values.

Reply 2224

bestfriends33

Original post by Tchombo

if 0 < x < 90 , -12 < B < 78 where B=x-12, you put the range boundaries in for x values.

Thanks! So you just subs the range values into the equation..

So for my question above would the range become -36.87 < x <323.13? :smile:

Reply 2225

MathsNerd1

Someone give me some foul questions for C3, I need to prepare for the outcome that happening in M2!

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Reply 2226

BobLoblawLawBlog

Original post by MathsNerd1

Someone give me some foul questions for C3, I need to prepare for the outcome that happening in M2!

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It's probably not that difficult, but it's the best I could come up with :colondollar:

.

Find

\dfrac{d}{dx}(x^{e^x})

. You are only allowed to use C3 methods though.

Reply 2227

Tendael

Original post by Tchombo

I rushed this but it's about finding limits for theta and multiplying the "y" expression by dx/d(theta) to integrate wrt theta I think

Did you forget to take it away from 5 at the end or am I missing something?

Reply 2228

MathsNerd1

Original post by brittanna

It's probably not that difficult, but it's the best I could come up with :colondollar:

.

Find

\dfrac{d}{dx}(x^{e^x})

. You are only allowed to use C3 methods though.

I'll try this now and post my answer for you to check? I'm sure I can already see the method though :smile:

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Reply 2229

MathsNerd1

Original post by brittanna

It's probably not that difficult, but it's the best I could come up with :colondollar:

.

Find

\dfrac{d}{dx}(x^{e^x})

. You are only allowed to use C3 methods though.

This just looks completely wrong, but who knows.

Is this correct?

ImageUploadedByStudent Room1370601946.900670.jpg

Edit: This is rubbish.
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(edited 10 years ago)

Reply 2230

MathsNerd1

Original post by brittanna

It's probably not that difficult, but it's the best I could come up with :colondollar:

.

Find

\dfrac{d}{dx}(x^{e^x})

. You are only allowed to use C3 methods though.

Ignore the last post, that's complete and utter rubbish, would this be it?

ImageUploadedByStudent Room1370602220.146727.jpg

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(edited 10 years ago)

Reply 2231

BobLoblawLawBlog

Original post by MathsNerd1

Ignore the last post, that's complete and utter rubbish, would this be it?

ImageUploadedByStudent Room1370602220.146727.jpg

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It looks similar to my answer, but I think your final answer is wrong.

I got

Spoiler

(edited 10 years ago)

Reply 2232

MathsNerd1

Original post by brittanna

It looks similar to my answer, but I think your final answer is wrong.

I got

Spoiler

Oh I had my base value wrong :-/ silly me -.-

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Reply 2233

BobLoblawLawBlog

Original post by MathsNerd1

Oh I had my base value wrong :-/ silly me -.-

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Reply 2234

AHarris

Original post by brittanna

It looks similar to my answer, but I think your final answer is wrong.

I got

Spoiler

What was your method to get this?

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Reply 2235

Better

Original post by justinawe

Have you done a good amount of practice for C4 yet, like Solomons and stuff? If so, starting the real C4 on Thursday should be fine, imo.

Yes mate I've finished all the Solomon for C4. Ah kk. Thanks for your input as always Justin!

Just a bit nervous whether I can finish them fine.

Reply 2236

RoyalBlue7

Original post by brittanna

It's probably not that difficult, but it's the best I could come up with :colondollar:

.

Find

\dfrac{d}{dx}(x^{e^x})

. You are only allowed to use C3 methods though.

Is this C3???!

Posted from TSR Mobile

Reply 2237

DELETED ACCOUNT

Original post by AHarris

What was your method to get this?

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You use implicit differentiation by taking logs on both sides.

y= x^(e^x)

lny= lnx^(e^x)

lny= e^x lnx

Differentiate
Use the product rule on the RHS

1/y(dy/dx)= e^xlnx + (e^x)/x

Multiply both sides by y

dy/dx = y( e^xlnx + (e^x)/x )

replace y with x^(e^x)

I am so sorry, but I cant do the whole fancy print screens they do. Someone else can do it for you :biggrin: