Edexcel A2 C4 Mathematics June 2016 - Official Thread

Original post by EricPiphany

I think it has to do with the fact that you dropped the absolute value sign, without ensuring that the argument would stay positive.

I looked again at the mark scheme, and there is a part where I think the equation is rearranged incorrectly.

Look at lines 6 and 7 of the solution for this question in the mark scheme

Reply 1622

Original post by anonwinner

I looked again at the mark scheme, and there is a part where I think the equation is rearranged incorrectly.

Look at lines 6 and 7 of the solution for this question in the mark scheme

'A' is an arbitrary constant and can be positive or negative. It's value wasn't set yet.
You can verify in your solution BTW that the initial condition doesn't hold.

Reply 1623

Original post by anonwinner

I looked again at the mark scheme, and there is a part where I think the equation is rearranged incorrectly.

Look at lines 6 and 7 of the solution for this question in the mark scheme

In fact, there is a slight error, there should be a plus-minus sign on the fifth line, before the exponential.

Reply 1624

Original post by EricPiphany

In fact, there is a slight error, there should be a plus-minus sign on the fifth line, before the exponential.

So should I have kept the modulus signs around 4 - 5h and then I would have got the correct answer?

Reply 1625

Original post by anonwinner

So should I have kept the modulus signs around 4 - 5h and then I would have got the correct answer?

Just change to 5h - 4, to make it positive at h = 4, notice that it can't change sign without t going to infinity. Most probably simpler to do it as in solution.

Reply 1626

Original post by EricPiphany

Just change to 5h - 4, to make it positive at h = 4, notice that it can't change sign without t going to infinity. Most probably simpler to do it as in solution.

At what stage can you just change it to 5h - 4?

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Original post by anonwinner

At what stage can you just change it to 5h - 4?

I would say as soon as you notice that 4 - 5(4) is negative. But what do I know :smile:

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Original post by EricPiphany

I would say as soon as you notice that 4 - 5(4) is negative. But what do I know :smile:

Ok thanks for the help

Reply 1629

kiasne

Original post by SeanFM

What specific problems are you having? :tongue:

Mainly just all of the integration stuff, most of the time I have no idea which method to use and when I revise one method I forget how to do the others..

Reply 1630

Kevin De Bruyne

Original post by kiasne

Mainly just all of the integration stuff, most of the time I have no idea which method to use and when I revise one method I forget how to do the others..

Maybe it's worth practicing the mixed exercise so you get tested on different ones?

If all else fails, try using every method until you find the right one (try as in, you probably won't get very far or have no idea to apply one method so move onto another one)

But practice is the key.

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Original post by SeanFM

But practice is the key.

are iygb similar to solomons?

Reply 1632

Kevin De Bruyne

Original post by tazza ma razza

are iygb similar to solomons?

I'm not sure, I'm too old to have used them properly. Worth a look though :tongue:

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Original post by SeanFM

I'm not sure, I'm too old to have used them properly. Worth a look though :tongue:

ahaha kk no worries, thanks :smile:

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Incidentally I am resitting some maths + further maths papers and was wondering, if i was to get a lower mark this year than I got last year in a paper, which mark would be noted - the higher 2015 mark or my most recent lower 2016 mark?

Reply 1635

username1162972

Original post by tazza ma razza

Highest mark out of the fdifferent sittings. But if you remark a paper and it drops the lowest mark goes.

Posted from TSR Mobile

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