Hellowo
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I am having a really hard time doing integration, I thought A2 differentiation was tough enough but A2 integration showed me it only gets worse.

My teacher teaches 1 subtopic in each lesson, so if I have a double, it'll be 2 subtopics in less than 2 hours, I really can't do it. I haven't understood the last subtopic and they're already rushing through the next one.

My friends who do further maths seem to be coping fine with their timetable and I'm flopping with just 3-4 subtopics per week.

I don't even know what I'm struggling with anymore, we're nearly finished with whole of chapter 11 in the Edexcel maths textbook and I have no clue in what I've been doing for the past few weeks.

Does anyone have time where I can pm them some questions?
I'm honestly really dumb when it comes to maths so it will probably take loads of explaining for me to get it (sorry).

Comment or pm me if you can help a bit, I'll really appreciate it!
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Xaodo
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(Original post by Hellowo)
I am having a really hard time doing integration, I thought A2 differentiation was tough enough but A2 integration showed me it only gets worse.

My teacher teaches 1 subtopic in each lesson, so if I have a double, it'll be 2 subtopics in less than 2 hours, I really can't do it. I haven't understood the last subtopic and they're already rushing through the next one.

My friends who do further maths seem to be coping fine with their timetable and I'm flopping with just 3-4 subtopics per week.

I don't even know what I'm struggling with anymore, we're nearly finished with whole of chapter 11 in the Edexcel maths textbook and I have no clue in what I've been doing for the past few weeks.

Does anyone have time where I can pm them some questions?
I'm honestly really dumb when it comes to maths so it will probably take loads of explaining for me to get it (sorry).

Comment or pm me if you can help a bit, I'll really appreciate it!
hey, i’m okay with a2 calc, feel free to drop me a pm
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laurawatt
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You can post any questions (and the work you’ve done so far on them) here and we can try and help

(On PM you can’t attach pictures and doing it on a thread means you’ll get help quicker)
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Xaodo
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(Original post by laurawatt)
You can post any questions (and the work you’ve done so far on them) here and we can try and help

(On PM you can’t attach pictures and doing it on a thread means you’ll get help quicker)
this
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Hellowo
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Name:  Screenshot 2021-03-04 at 09.30.36.png
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Size:  35.3 KBName:  Screenshot 2021-03-04 at 09.30.30.png
Views: 7
Size:  99.7 KBHi, sorry for responding so slow, only just got time to come on.
Here's an example that I'm stuck on.

For limits, when you convert then to a 'u' version, do you then still use that "u" version when you put u-sub back in?

So I've got to the point where you try and get a value, but I used ln4 and ln3 instead of the new 'u' ones (root 2 and 1). I seem to not get the answer with the ln4 and ln3...not sure if it's me calculating it wrong or something.
I don't know if I'm supposed to be using root 2 and 1 instead.

Thank you in advance
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Hellowo
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(Original post by laurawatt)
You can post any questions (and the work you’ve done so far on them) here and we can try and help

(On PM you can’t attach pictures and doing it on a thread means you’ll get help quicker)
Oh I didn't know you can't pm pictures, thank you for letting me know!
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mqb2766
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After working out the u limits and expressing the integral in terms of u and du, you can "forget" about the original version in terms of x. So the limits in the second half of the solution are sqrt(2) and 1, as shown in the solution.

The transformed integral has "u" as the horizontal axis, and you want to find the area between the function f(u) and the u axis.
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Hellowo
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(Original post by mqb2766)
After working out the u limits and expressing the integral in terms of u and du, you can "forget" about the original version in terms of x. So the limits in the second half of the solution are sqrt(2) and 1, as shown in the solution.

The transformed integral has "u" as the horizontal axis, and you want to find the area between the function f(u) and the u axis.
Oh I see, by forgetting do you mean I can just sub in root 2 into the u version of the integral?
I've realised if I sub root 2 into u^6/3, I get 8/3 like if I subbed ln4 into the x version.

Also sorry, what do you mean by transformed integrals (I probably should know but unfortunately I don't...)? I think our class did areas and curves last lesson but I'm still struggling with these so haven't got around to those exercises yet
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the bear
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(Original post by Hellowo)

Also sorry, what do you mean by transformed integrals (I probably should know but unfortunately I don't...)?
it just means the integral after you have changed the variable. you do not need to draw a picture or anything.
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mqb2766
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(Original post by Hellowo)
Oh I see, by forgetting do you mean I can just sub in root 2 into the u version of the integral?
I've realised if I sub root 2 into u^6/3, I get 8/3 like if I subbed ln4 into the x version.

Also sorry, what do you mean by transformed integrals (I probably should know but unfortunately I don't...)? I think our class did areas and curves last lesson but I'm still struggling with these so haven't got around to those exercises yet
Yes. The integration problem has been transformed from x-space to u-space, via the substitution. I used "transformed" to make clear they're, x&u, different variables. I was referring to integration using substitution.
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Hellowo
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(Original post by the bear)
it just means the integral after you have changed the variable. you do not need to draw a picture or anything.
Right, thank you for clarifying!
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the bear
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(Original post by mqb2766)
Yes. The integration problem has been transformed from x-space to u-space, via the substitution. I used "transformed" to make clear they're, x&u, different variables.
this makes it sound much too complicated for an A level student
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Hellowo
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(Original post by mqb2766)
Yes. The integration problem has been transformed from x-space to u-space, via the substitution. I used "transformed" to make clear they're, x&u, different variables.
I understand now thank you very much.

I also finally got the answer now, I've just forgotten to subtract the numbers I'm supposed to subtract...

But you've really been helpful in clarifying stuff so thank you!
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mqb2766
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(Original post by the bear)
this makes it sound much too complicated for an A level student
Possibly, but if they're getting confused over which values to use, saying it's a new (transformed) problem completely in terms of u, so you forget about the old x version isnt?
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Hellowo
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Oh um, I got another question, how do you go from 16ln2 - 16ln1 to 8ln2? I get the division bit but I don't know how they went from 16 to 8?
Sorry it's another dumb question
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mqb2766
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16ln(sqrt(2)) - 16ln(1)
The root is important.
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Hellowo
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(Original post by mqb2766)
16ln(sqrt(2)) - 16ln(1)
The root is important.
Ah yes I was looking at my x-version again sorry.


But I still don't know how it goes to 8ln2 though?
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mqb2766
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(Original post by Hellowo)
Ah yes I was looking at my x-version again sorry.


But I still don't know how it goes to 8ln2 though?
ln(1) =...
ln(2^(1/2)) = ...
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Hellowo
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(Original post by mqb2766)
ln(1) =...
ln(2^(1/2)) = ...
I still don't quite understand what the second line is...
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mqb2766
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(Original post by Hellowo)
I still don't quite understand what the second line is...
It's one of the standard log rules
log(a^b) = b*log(a)
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