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Edexcel C2 20th May 2015 *Official Thread*

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Original post by KINGYusuf
Guys you know if d2y/dx2 is > 0 it's a MINIMUM

d2y/dx2 < 0 it's a MAXIMUM

If d2y/dx2 = 0 is it point of inflection? What do you do next 3rd differential or something idk? How can you make sure


You wouldn't do anything after that except for if you have time at the end then run through the question again
Guys when do I need to change from degrees to radians mode on my calc? HELP
Original post by Haych97
Just come across this question on an IAL, have no idea how to do it and not sure if its part of our spec


12x= 1 x nx
x's cancel therefore nb=12
Original post by Haych97
The question attached



imahhhhge1.jpg

Hope you understand this :P Because a circle is 2pi and if you divide a circle into 6 little triangles, you get the angle pi/3
Original post by sharp018
Guys when do I need to change from degrees to radians mode on my calc? HELP


misread the question: Most of the time area of a sector, area/ length. They would probably want you to use sin/cosine in radians too.

Also sometimes in trig identities
(edited 8 years ago)
Soo confused?


in some question the geometric sequence power r has been subtracted by minus 1 in other question it remains unchanged.
how do we know when to subtract 1 or leave r with no power?
Original post by .JC.
Which paper?


Someone on this thread linked it so I tried to attempt it and got nowhere:frown:

http://qualifications.pearson.com/content/dam/pdf/International%20Advanced%20Level/Mathematics/2013/Exam%20materials/Question-paper-Paper-C12-(WMA01)-June-2014.pdf
Guys what year is the hardest maths paper?


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Original post by frozo123
yeah just use the 1 + nx ting


Care to elaborate?
Original post by sharp018
Guys when do I need to change from degrees to radians mode on my calc? HELP


Whenever the question is to do with sectors and area of triangles. Also for some trig equations, it will state the interval in which would imply whether you use radians or degree.
Original post by frozo123
12x= 1 x nx
x's cancel therefore nb=12


part b
Reply 1331
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.JC.
14
Original post by Haych97


Don't think that's anything to do with our spec.
Original post by frozo123
If d2y/dx^2 is 0, if you differentiate it again and does not equal 0, then it's a point of inflexion


& if in the 3rd differential is 0? Then it's inconclusive?
(edited 8 years ago)
Reply 1333
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Original post by .JC.
Care to elaborate?


Its called equating co-effiecients

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Original post by .JC.
Care to elaborate?


in the formula booklet there are two formulae for binomial expansions

one is in the form ( 1 +x)^n
where the first number has to be 1
so if I had (3+6x)^ 4
I would have to do first of all ( 3(1+2x) ) ^4 then 81 (1 +2x)^4
then you just follow the formula
it's easier than the nCr crap
Original post by jtlmao
Guys what year is the hardest maths paper?


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January 2010 its only 54 to get an A
Original post by mrchemistry
Do you guys think we would be expected to know formulas for 3d shapes? E.g. cylinder, cone, sphere, etc?


I pretty certain it will come up and I hope it does. It's really easy and worth a lot of marks.
but if I'm using the equation for example when the angle given is in radians and I want to find the arc length, so the formula is theta x r, do I still need to switch to radians mode?

Original post by kkboyk
Whenever the question is to do with sectors and area of triangles. Also for some trig equations, it will state the interval in which would imply whether you use radians or degree.
Original post by sharp018
Guys when do I need to change from degrees to radians mode on my calc? HELP


Whenever you see superscript c / rad - usually this is for angles in triangles or circle questions

Also if you're asked to solve for x in a sin/cos/tan question with ...pi<x<...pi you'll need to use radians.
Reply 1339
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Original post by sharp018
but if I'm using the equation for example when the angle given is in radians and I want to find the arc length, so the formula is theta x r, do I still need to switch to radians mode?


Yes thats the whole point

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