# Edexcel A2 C3 Mathematics 12th June 2015Watch

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3 years ago
#1081
(Original post by imedico10)
i'll try my best... according to f(x) x must be bigger than zero.

the graph for fg is 3e^x +x^2 ..... is you sub x=0 you get y as 3.... after 3... y keeps increasing exponentially so the range (values of y) is bigger than 3. hope this helps

this image shows what im trying to say
Omg thaaaaaanks! so in these questions I just substitute the domain to find the range and draw a graph right?
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3 years ago
#1082
Do you have to know how to derive the factor formulae? ExamSolutions didn't mention it in his factor formulae videos so I guess not but I just wanna make sure...
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3 years ago
#1083
(Original post by Gome44)
X^2 + 3 is always positive anyway, so you can just remove the mod sign
Ok, what if it was:

|x^2 - 36| + 2x

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3 years ago
#1084
(Original post by Medicjug)

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a) Use the double angle formula to expand Rcos(x-#) (pretending # is alpha):L

Rcos(x - #) ---> Rcosxcos# + Rsinxsin#

Take coefficients of cosx and sinx:

Rcos# = 1 and Rsin# = ROOT(3)

Since Rcos#/Rsin# ----> tan# (where R cancels out)

-> tan# = Root(3)/1

solve tan^-1(root(3)/1) to get your value for #. # = (pie)/3

To find R -----> R^2 = 1^2 + (root(3))^2
R = root(4) = 2
Leave in the form - 2cos(x - (pie)/3) where you have a value for # as (pie)/3

b) Use your values in part a) to solve b)! Very much like C2!!

Hope this helps!!
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3 years ago
#1085
(Original post by it's a me, mario)
Ok, what if it was:

|x^2 - 36| + 2x

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Doubt this will ever come up, but here's how I would do it:

Consider when the inside of the | | sign is negative. This is when -6<x<6. A property of the mod sign is |y| =-y when y<0. In this case y=x^2 -36. So from -6<x<6, the curve you need to sketch is -(x^2 -36) +2x, and for the other parts you need to sketch x^2 -36 +2x
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3 years ago
#1086
(Original post by Medicjug)

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I assume you've done the first part? In the second, you should end up with cos(2x-α)-cos(x)=0

What teeEm has done in the solutions is use the periodicity of cos, however, you can also write this in an alternate form using factor formula (in the formula book)
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3 years ago
#1087
(Original post by Cowy97)
the first part r= sqrt(1^2+sqrt3^2)
and a tan^-1 (sqrt3/1)
i think
and i would be ****ed if b came up in the exam
if only.. many would ...
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3 years ago
#1088
(Original post by Medicjug)

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Not for the faint hearted ...
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3 years ago
#1089
(Original post by TeeEm)
if only.. many would ...
Teeem are you a student or a teacher

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3 years ago
#1090
(Original post by gcsestuff)
Teeem are you a student or a teacher

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neither ...
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3 years ago
#1091
Can someone confirm that integration and implicit differentiation are not part of edexcel C3. Thanks.

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3 years ago
#1092
(Original post by vuvuzela)
Can someone confirm that integration and implicit differentiation are not part of edexcel C3. Thanks.

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confirmed
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3 years ago
#1093
(Original post by TeeEm)
neither ...
Are you an examiner?

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3 years ago
#1094
(Original post by gcsestuff)
Are you an examiner?

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I am a mathematician
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3 years ago
#1095
(Original post by TeeEm)
I am a mathematician
can you help me with domain and range please?
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3 years ago
#1096
(Original post by s234590)
can you help me with domain and range please?
I will be if you have a specific question when I get back from my morning walk
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3 years ago
#1097
(Original post by TeeEm)
confirmed
Thanks so much

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3 years ago
#1098
(Original post by Medicjug)

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Which IYGB paper is that?
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3 years ago
#1099
(Original post by Nurishment)
Which IYGB paper is that?
I think it's p

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3 years ago
#1100
(Original post by Gome44)
I assume you've done the first part? In the second, you should end up with cos(2x-α)-cos(x)=0

What teeEm has done in the solutions is use the periodicity of cos, however, you can also write this in an alternate form using factor formula (in the formula book)
Thanksss everyone. How would writing it in cosP+cosQ help?

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