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Edexcel A2 C3 Mathematics 12th June 2015

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Does anyone understand how to do q3c in this international paper?
http://qualifications.pearson.com/content/dam/pdf/A%20Level/Mathematics/2013/Exam%20materials/6665_01R_que_20130613.pdf

Apparently k = positive or negative root 50

xoxo
Original post by gcsestuff
ImageUploadedByStudent Room1433523141.107878.jpg

Can someone help me with this. I hate these questions:frown:

Ideally can I have a numerical method as I hate graphs


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Not sure what part you mean?
But for a, just find g(4) and then sub the value you get into f(x)

For inverses, I like to say "let f^-1(x) = y
Then you go to the f(x) equation, replace f(x) with x and replace any x with y
Then you rearrange to find y

c is a standard graph, obvious asymptote and the typical shape you get with graphs like y = 1/x

For d, you just need to solve two equations. The expression in moduli can be equal either to 3 or to -3, since when you take the modulus of either you get 3.
Original post by radhikagulati
Does anyone understand how to do q3c in this international paper?
http://qualifications.pearson.com/content/dam/pdf/A%20Level/Mathematics/2013/Exam%20materials/6665_01R_que_20130613.pdf

Apparently k = positive or negative root 50

xoxo


Try drawing the cos graph, or maybe use CAST.
Original post by 1 8 13 20 42
Not sure what part you mean?
But for a, just find g(4) and then sub the value you get into f(x)

For inverses, I like to say "let f^-1(x) = y
Then you go to the f(x) equation, replace f(x) with x and replace any x with y
Then you rearrange to find y

c is a standard graph, obvious asymptote and the typical shape you get with graphs like y = 1/x

For d, you just need to solve two equations. The expression in moduli can be equal either to 3 or to -3, since when you take the modulus of either you get 3.


https://b3755649dbd1afe3db91a899c3b9837b22326254.googledrive.com/host/0B1ZiqBksUHNYMG14YWtobVJUUms/for-Edexcel/Solomon%20F%20QP%20-%20C3%20Edexcel.pdf
8c? Idk how to do it lol
and do we need to know sec, cosec and cot graphs? ffs
Original post by frozo123


You should have dy/dx from part a
set it equal to zero and rearrange it to get the non-logged x's together

Yes, I think so. They aren't too bad, and if you forget one you can probably make a very educated guess at it by considering what happens at different values of x.
Original post by humayra.ac
how do you find a starting value for an iteration formula ?? from solomon a paper


Has anyone answered this I want to know the answer too
Reply 866
Avatar for Hudl
Hudl
16
Original post by studentwiz
Has anyone answered this I want to know the answer too


You can pick any value but looking at the question it is common sense to pick 2 as based on the sketch you drew in the previous section you know it crossed near that asymptote
Original post by Hudl
You can pick any value but looking at the question it is common sense to pick 2 as based on the sketch you drew in the previous section you know it crossed near that asymptote


what question? the range of k?
Reply 868
Avatar for Hudl
Hudl
16
Original post by studentwiz
what question? the range of k?


I thought you wanted to know how to find the starting value for the iteration formula like in the example in Solomon paper A Q8)
Original post by Hudl
I thought you wanted to know how to find the starting value for the iteration formula like in the example in Solomon paper A Q8)


oh right so how did they get 3
Original post by 1 8 13 20 42
Not sure what part you mean?
But for a, just find g(4) and then sub the value you get into f(x)

For inverses, I like to say "let f^-1(x) = y
Then you go to the f(x) equation, replace f(x) with x and replace any x with y
Then you rearrange to find y

c is a standard graph, obvious asymptote and the typical shape you get with graphs like y = 1/x

For d, you just need to solve two equations. The expression in moduli can be equal either to 3 or to -3, since when you take the modulus of either you get 3.


Sorry, it was the last part of the question. Do I square both sides??


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Reply 871
Avatar for Hudl
Hudl
16
Original post by studentwiz
oh right so how did they get 3


You can start with any value, the value you start with doesnt matter. The further away you are from the true value with the value of Xo you start with the longer the iteration will take. I was simply telling you how to pick an appropriate value, use things like asymptotes and known values / coordinates to make a good guess of what to use as your approximation
Original post by gcsestuff
Sorry, it was the last part of the question. Do I square both sides??


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You can but I don't think squaring is necessary; like I said you are taking the absolute value of what is in between the modulus signs and getting out 3; therefore the actual value can be 3 or -3
Original post by Hudl
You can start with any value, the value you start with doesnt matter. The further away you are from the true value with the value of Xo you start with the longer the iteration will take. I was simply telling you how to pick an appropriate value, use things like asymptotes and known values / coordinates to make a good guess of what to use as your approximation


ohh ok I understand now thanks!:smile:
Reply 874
Avatar for Cosmi
Cosmi
2
https://07a69ccf283966549a9350d1a66951a7bc96e2dc.googledrive.com/host/0B1ZiqBksUHNYZ0JQM1NRcmdHdXM/January%202014%20(IAL)%20QP%20-%20C3%20Edexcel.pdf
https://07a69ccf283966549a9350d1a66951a7bc96e2dc.googledrive.com/host/0B1ZiqBksUHNYZ0JQM1NRcmdHdXM/January%202014%20(IAL)%20MS%20-%20C3%20Edexcel.pdf

For 5b, why is x = 3.742?

My calculator reports 3rt2(cos(0.295 + pi/4)) as 2 (0.295 is unrounded).

Edit: Also, where did the solution for 8c come from? The question seems like they're asking where it crosses the x-axis to me, and it doesn't unless k = 0?
(edited 8 years ago)
Original post by 1 8 13 20 42
You can but I don't think squaring is necessary; like I said you are taking the absolute value of what is in between the modulus signs and getting out 3; therefore the actual value can be 3 or -3


Thanks I've got it now :smile:)


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Does anyone else do graph reflections and Inverses by looking at the reflection in the calculator screen? Haha


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Reply 877
Avatar for Cosmi
Cosmi
2
Original post by gcsestuff
Does anyone else do graph reflections and Inverses by looking at the reflection in the calculator screen? Haha


Posted from TSR Mobile


Not a bad idea lol, might look a bit weird tho.
Need an A* in maths for my economics offer.

Worried that this year the C3 and C4 papers will be difficult.

Typically average 70/75 in past papers but noticed they gotten much harder the last few years.

How will this year's exams compare?

Thanks :smile:
Reply 879
Avatar for TeeEm
TeeEm
19
Original post by MattEconomics
Need an A* in maths for my economics offer.

Worried that this year the C3 and C4 papers will be difficult.

Typically average 70/75 in past papers but noticed they gotten much harder the last few years.

How will this year's exams compare?

Thanks :smile:


Then practice with something more difficult

http://www.thestudentroom.co.uk/showthread.php?t=3361905
http://www.thestudentroom.co.uk/showthread.php?t=3361867
(edited 8 years ago)

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