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Edexcel Core 3 - 21st June 2016 AM

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Are there any formulas that I need to know the prove for in C3
(edited 7 years ago)
Hey guys for question 2b in C3 SOLOMON E I keep finding that for questions like that I end up with only the tanx = 2 solution and I dont end up with the cos2x = 0 solutions. I think this is because im dividing both sides by cos2x. Is there something im missing? Or should I just remember to never divide both sides by cos etc?

https://b3755649dbd1afe3db91a899c3b9837b22326254.googledrive.com/host/0B1ZiqBksUHNYMG14YWtobVJUUms/for-Edexcel/Solomon%20E%20QP%20-%20C3%20Edexcel.pdf
(edited 7 years ago)
Original post by SeanFM
The domain is immediate (in f(g(x)), the domain is precisely the domain of g(x) - after all, if you try to put in anything else then it will be invalid at the first hurdle!

The range, well.. you have to take the range of g(x) and see how it reacts to f(x) to find the range, as f(x) is the last thing that you compute, but with a domain of the range of g(x) (since you are putting in values of g(x)).


Thank you


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Original post by imran_
just curious, do i have to learn the factor formula thing for trig ? ive never seen it come up on past papers and worried about iut


It's come up before, just look back at factor formulae from AS
Doesn't take long to learn


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I know the specification mentions arcsinx arccosx and arctanx but what do we actually have to know about them? Our teachers have just told us that it's the same as sin^(-1)x etc and that's it
(edited 7 years ago)
Original post by Bloom77
It's come up before, just look back at factor formulae from AS
Doesn't take long to learn


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What is this factor formula thing for trig you speak of?
Original post by LoveToArgue
I know the specification mentions arcsinx arccosx and arctanx but what do we actually have to know about them? Our teachers have just told us that it's the same as sin^(-1)x etc and that's it


sin(arcsin(x)) = x, arcsin(sin(x)) = x, etc. Maybe the shape of the graph as well but just use your calculator and put in different points (eg x=0, y= arcsin0 = 0).
Original post by LoveToArgue
I know the specification mentions arcsinx arccosx and arctanx but what do we actually have to know about them? Our teachers have just told us that it's the same as sin^(-1)x etc and that's it


You are going to need to know how to draw the graphs and what the domain and range will be of these graphs.
Reply 368
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Jold
1
Anyone got any tips on avoiding silly mistakes other than just being overly cautious when in the exam? The only marks Im losing are silly mistakes but if I want an A* overall I really feel I need to nail this exam in case C4 doesn't go well, considering my other further maths exams haven't gone great so far I'm just relying on getting an A* in maths!
Original post by Jold
Anyone got any tips on avoiding silly mistakes other than just being overly cautious when in the exam? The only marks Im losing are silly mistakes but if I want an A* overall I really feel I need to nail this exam in case C4 doesn't go well, considering my other further maths exams haven't gone great so far I'm just relying on getting an A* in maths!


Same! What I found to be working is to take my time doing questions and reviewing my solution after finishing it, and then moving on. Most of my silly mistakes are due to me rushing.
Guys what are the hardest papers up to date for C3? (edexcel have been very annoying this year) Excluding IAL because they are C34...
Reply 371
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Jold
1
Original post by eftio.gea
Guys what are the hardest papers up to date for C3? (edexcel have been very annoying this year) Excluding IAL because they are C34...


Off the top of my head, the hardest paper I've done recently was the June 2013 Reserve paper I think
Original post by eftio.gea
Guys what are the hardest papers up to date for C3? (edexcel have been very annoying this year) Excluding IAL because they are C34...


2013 and 2015 are the hardest I can remember
The original retracted 2013 paper is a bit tricky but nothing spectacular
Original post by SeanFM
sin(arcsin(x)) = x, arcsin(sin(x)) = x etc

This isn't completely correct. Whilst it is indeed true that sin(arcsin x) = x, it is only true for values of x between 1 and -1. The case of arcsin(sin x) is more complicated, and it is in fact a periodic triangular waveform.
Reply 374
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linaxq
2
Original post by NotNotBatman
It's quite late in the academic year and I haven't seen a C3 thread yet. If there are any extra resources you know of, please post them.

Specification and Formula Booklet:
Specification
Formula Booklet

Revision material
Examsolutions:
Video Tutorials
Video Solutions to Past Papers

m4ths (ukmathsteacher on YouTube)
m4ths

Video tutorials and solutions to Solomon Papers
Hegarty Maths

Various C3 revision material (notes/worksheets/solution bank etc) :
Various C3 revision material
More C3 revision material

Madasmaths(made by @TeeEm)
Worksheets
I.Y.G.B. Practice Papers

Past papers/practice papers
Edexcel papers
Edexcel Bronze/silver/Gold papers
Edexcel Practice Papers
Solomon Papers
Elmwood Papers
I.Y.G.B. Practice Papers
AEA Papers (C3 AND C4 QUESTIONS AIMED AT THE TOP 10%)
Crashmaths ( by @kingaaran )


The AEA papers link just redirects me to the edexcel exams?
Original post by linaxq
The AEA papers link just redirects me to the edexcel exams?


AEA papers are made by edexcel.
Original post by Bloom77
You know there's a rule that

The domain of f(X) is the same as the range of the inverse of f(X) and vice Versa.

Is there a similar rule for combined functions like fg(X) when they ask us to find range and domain?


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do you have a question i could try on the fg(x) function?
Hey guys for question 2b in C3 SOLOMON E I keep finding that for questions like that I end up with only the tanx = 2 solution and I dont end up with the cos2x = 0 solutions. I think this is because im dividing both sides by cos2x. Is there something im missing? Or should I just remember to never divide both sides by cos etc?
Original post by Zacken
Pretty handwriting, by the way. :yep:


How cute
I know it's a core 1 question but a mistake I slip up on everytime: what order do you perform a graph transformation i.e: stretch or translation first??

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