Edexcel C3,C4 June 2013 Thread

OP

Original post by yaboy

is anyone else finding some of the questions on c3 solomon papers ridiculously hard???

I thought we never did logs in c3 then I end up seeing a logs question on the first page lol

They are hard, push through young soldier and you realize log questions are just algebra.

You pretty much just always do the same to both sides.

The trick is always simplify, take out numbers where you can and of course write clearly.

Reply 982

OP

Original post by S1L3NTPR3Y

So in terms of past papers for C3/C4 there are: Edexcel June 2005 - January 2013 (16 papers); Solomon A through to L (12 papers) and the Elmwood papers (4 papers). Making a total of 32 papers for each, is this correct?

Wow thanks for this.

I didn't realise how many there are....I need to pick my game up and start doing 3 a day on the weekends for D1 C3 C4....

Come at us though! I'm feeling ready for this

Reply 983

Original post by yaboy

is anyone else finding some of the questions on c3 solomon papers ridiculously hard???

I thought we never did logs in c3 then I end up seeing a logs question on the first page lol

I remember thinking that. I'm sure there is a question where you have to prove by contradiction that log(base2) 3 is irrational.

But I'm certain nothing like that would ever appear on the exam. :smile:

Posted from TSR Mobile

Reply 984

OP

Can anyone please explain the trig identity TRIANGLES.

I have no clue how to derive them, images would help too. Thanks.

Reply 985

yaboy

Can someone explain how sin(x)=cos(pi/2-x)?

I understand the trig graph is moved back but would this not give cos(x+pi/2)?

(edited 11 years ago)

Reply 986

posthumus

20

Original post by yaboy

Can someone explain how sin(x)=cos(pi/2-x)?

I understand the trig graph is moved back but would this not give cos(x+pi/2)?

I think you move it forward by pi/2 :smile:

Reply 987

Revisionbug

1

Original post by dan94adibi

Well you've done really well to finish off almost all past papers.
What you need to do after is go over the past papers and the questions you've done see where you've dropped marks.
Do do those questions and see if you can do them correctly if not then you need to go over them and see where the problem is.

Omg i just realised you misunderstood me y didnt i read this b4!! I meant to say im almost finished with content not past pprs n solomons LOL srry bout that :/ anyway iv gt one mre q iv come across doing qs of certain topics from solomon worksheets shud i do this as opposed to the questions in the book or shud i do qs in book aswell i cnt do both :/ as i hv c1-4 n s1 m1 in june may aswell as 2 bio units so erm solomon worksheets or mixed excercisrs in book atm im thinking of doing solomon worksheets to a couple of past pprs to solomons then just working on my weaknesses wdyu guys think?

Reply 988

yaboy

Original post by posthumus

I think you move it forward by pi/2 :smile:

still cant understand why its cos(pi/2-x)

Reply 989

usycool1

19

Original post by yaboy

still cant understand why its cos(pi/2-x)

Try expanding out cos(pi/2 - x) using the addition formula. :smile:

Reply 990

posthumus

20

Original post by yaboy

still cant understand why its cos(pi/2-x)

I hope you find this useful:
pi graph shit.png

probably not the best of color choices :tongue:

You want the cos graph to shift right by pi/2 (90 degrees).. so cos(pi/2 -x) will give you the green line... so would cos(x - pi/2) for that matter :smile:

Now you said shift it pi/2 to the left... cos(pi/2 +x) [or yh cos(x+pi/2) for that matter :tongue:

]. This graph is shown by the blue line in the image :smile:

EDIT: In fact I think that gives a -sin(x) graph :smile:

(blue line), not too sure about that though.

(edited 10 years ago)

Reply 991

masryboy94

well this is weird, im finding the soloman papers for C4 easier than the exam papers (based on jan 2013), hope it stays that way ! i've gotten to the stage where im starting to enjoy C4 :rolleyes:

yep even vectors :eek:

im really hoping for that A* !!

Reply 992

Original post by masryboy94

well this is weird, im finding the soloman papers for C4 easier than the exam papers (based on jan 2013), hope it stays that way ! i've gotten to the stage where im starting to enjoy C4 :rolleyes:

yep even vectors :eek:

im really hoping for that A* !!

I'm at the same point, although the first past paper I did after about 7 Solomons just looked simple in comparison, was Jan 2013 a hard paper or something?

Posted from TSR Mobile

Reply 993

masryboy94

Original post by MathsNerd1

I'm at the same point, although the first past paper I did after about 7 Solomons just looked simple in comparison, was Jan 2013 a hard paper or something?

Posted from TSR Mobile

it was a standard paper in my opinion, except for part c and d in question 5, caught me out a bit, but i got it now.but in my opinion if our exam is like jan 2013 i would be so happy !

Reply 994

Original post by masryboy94

it was a standard paper in my opinion, except for part c and d in question 5, caught me out a bit, but i got it now.but in my opinion if our exam is like jan 2013 i would be so happy !

Oh okay then, I'll just have to wait until I do it as a mock but I'll keep in mind about part c and d and hopefully they won't catch me out :biggrin:

Posted from TSR Mobile

Reply 995

justinawe

19

Original post by MathsNerd1

I remember thinking that. I'm sure there is a question where you have to prove by contradiction that log(base2) 3 is irrational.

But I'm certain nothing like that would ever appear on the exam. :smile:

Posted from TSR Mobile

lol, in a Solomon paper? I don't think most A-level students have even come across that sort of queation before.

Reply 996

Original post by justinawe

lol, in a Solomon paper? I don't think most A-level students have even come across that sort of queation before.

Yeah, I'm sure it was one of the last papers but I must admit that it caught me out for a moment, but only because I didn't have a clear definition of what irrational meant, but yeah, no one else could even attempt it at my 6th form, they just completely skipped it.

If they gave me anything like that in the exam I'll now be ready :tongue:

On a side note, yesterday my teacher printed out the information that told me where I lost my marks and I already knew about 9 that I lost but then I apparently lost 2 more as I can't differentiate anymore, I'm seriously going to take my time in this attempt to make sure nothing like that would happen again.

Posted from TSR Mobile

Reply 997

RoyalBlue7

19

Original post by yaboy

still cant understand why its cos(pi/2-x)

Cos is an even function I.e. cos(x)=cos(-x), cos x graph doesn't change if it is reflected over the y axis as the y axis is a line of symmetry.

You very well know that cos (x-π/2) is sin x . So sin x = cos (-(x-π/2))=cos (π/2-x).

You can't say that cos (-(x-π/2)) is a reflection of the sin curve over the y axis because you have shifted the y axis by π/2 units towards x increasing . Its a reflection of the sine curve on the vertical x=-
π/2 which is a line of symmetry of the sin curve.
Y=f(-(x±a)) is NOT a reflection of y=f(x±a) over the y axis. This is because you are reflecting over the vertical x=±a. Like if a=3 then -(x+3) is -3-x which is like the y axis as gone 3 units back and the x increasing axis is now x decreasing and vice versa.

Posted from TSR Mobile

(edited 10 years ago)

Reply 998

OP