# Edexcel A2 C3 Mathematics 12th June 2015Watch

This discussion is closed.
3 years ago
#961
(Original post by BBeyond)
I found it easier to just expand the tan pi-theta to get a quadratic then solve that
Exactly how I did it. Was a bit more arduous but ensured I didnt miss the second solution
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3 years ago
#962
(Original post by humayra.ac)
This is part a which ive done
Use the identities for (sin A + sin B) and (cos A + cos B) to prove that sin 2x + sin2y/ cos2x +cos2y ≡ tan (x + y)

part b im stuck on ...

Hence, show that tan 52.5° = root6 − root3 − root2 + 2.

in the mark scheme it says let x=30 and y=22.5 which I understand why,
but then why does it afterwards say ∴ tan (30 + 22.5) = sin 60 + sin 45/ cos 60 + cos 45

(https://b3755649dbd1afe3db91a899c3b9...%20Edexcel.pdf)
Because 60 = 2x and 45 = 2y, and sin 2x + sin 2y/cos 2x + cos 2y = tan (x + y) = tan 52.5.
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3 years ago
#963
oh god, that simple thanks

(Original post by bored565)
Because 60 = 2x and 45 = 2y, and sin 2x + sin 2y/cos 2x + cos 2y = tan (x + y) = tan 52.5.
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3 years ago
#964
The curve has a stationary point in the interval [0, 1]. --> what does the interval bit mean
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3 years ago
#965
(Original post by humayra.ac)
The curve has a stationary point in the interval [0, 1]. --> what does the interval bit mean
The x coord of the stationary point is between 0 and 1 ([] mean inclusive, ie, including 0 and 1, () means not inclusive)
1
3 years ago
#966
alrite. C3 and Unit 4 physics next.

Revision Begins
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3 years ago
#967
(Original post by humayra.ac)
The curve has a stationary point in the interval [0, 1]. --> what does the interval bit mean
Means the x value of the SP is somewhere between 0 and 1. The '[xxxxx]' is conventional in giving the range in which a value lies. Eg, 2 is in the interval [1.5, 2.2]
1
3 years ago
#968
Alright, a tad bit confused here for the R-Alpha method stuff.

http://gyazo.com/4594360d328674d231bd6c97e4d5f7d6

Above is a question. This seems fairly easy right? Normally, i can find R and Alpha easily. So, in this case i would find R = 2 and a = pi/6

However alpha is pi/3

I got a = pi/6 by using the formula, which is given by the book and my teacher, a = tan^-1(b/a). However clearly that is wrong. Now, i understand how they got pi/3, but everytime i do a different exam paper, the tan^-1(b/a) formula works. This paper is the only time it didn't, and we were required to use the proof method, for 4 marks. Am i missing something here or did edexcel simply screw up?

edit: nevermind i understand it now.
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3 years ago
#969
which paper do you guys find the hardest? I have a economics unit 3 exam the day before C3, therefore I don't have that much time to prepare for C3.... I've done all the papers C3 from 2009 to 2014, but that was like 2 weeks ago and I'm afraid that I'm gonna forget C3.... Ah, I ****ing hate having exams in consecutive days....
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3 years ago
#970
(Original post by Bustamove)
which paper do you guys find the hardest? I have a economics unit 3 exam the day before C3, therefore I don't have that much time to prepare for C3.... I've done all the papers C3 from 2009 to 2014, but that was like 2 weeks ago and I'm afraid that I'm gonna forget C3.... Ah, I ****ing hate having exams in consecutive days....
I've got physics the day before.

I'm going to go though every trig question from past papers and Solomon. Then do as many iygb papers as I can(they've been all over this thread)

I think from 1till 9 I can get trig and about 4 papers done

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3 years ago
#971
Question: What papers are the most testing - Xtreme or Solomon?
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3 years ago
#972
Hi guys, how difficult do you think this years paper will be - compared to the previous year. I have a bad feeling this could be a tricky paper this year :/
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3 years ago
#973
Why is the 2013 paper so hard

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3 years ago
#974
(Original post by raypalmer)
Why is the 2013 paper so hard

Posted from TSR Mobile
writing a paper is not an exact science, so occasionally it turns out to be too easy or too hard
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3 years ago
#975
(Original post by NCHOWD)
Hi guys, how difficult do you think this years paper will be - compared to the previous year. I have a bad feeling this could be a tricky paper this year :/
I hope that it is truly hard, but I have a feeling it will be very standard
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3 years ago
#976
Xtreme?

never heard of them..
where did you get them?
0
3 years ago
#977
(Original post by TeeEm)
I hope that it is truly hard, but I have a feeling it will be very standard
Harder!? lower grade boundaries? what makes you think it will be easier? Last years paper was easy and so was the year before
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3 years ago
#978
(Original post by NCHOWD)
Harder!? lower grade boundaries? what makes you think it will be easier? Last years paper was easy and so was the year before
gut feeling it will be standard.
(but I wish the hardest ever...)
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3 years ago
#979
(Original post by TeeEm)
gut feeling it will be standard.
(but I wish the hardest ever...)
Fair enough
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3 years ago
#980
(Original post by Artfanatic)
Question: What papers are the most testing - Xtreme or Solomon?
Xtreme?

never heard of them..
where did you get them?
0
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