edexcel C2 23rd May 2018 unofficial mark scheme

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zayzay1999

Guys, for q8 ii I solved it all correctly and go 1/4 and -1/3 but I stupidly did the solutions in the form cos theta, so all my answers were wrong at the last stage. How many marks will I lose considering all the actual solving was right????

Reply 181

ChezPlayz

I got 51.412 for the first one as I used decimal rather than 4sq2 as that’s what my calculator gave. Would that be okay? There would be a range of answers on the Mark scheme of about 1dp surely?

Reply 182

tinaaaa

Original post by RiRi_97

You have typed it in wrong. Inside the numerator bracket it needs to be (1-(-0.9)^12) not (1-(-0.9^12) )
Hence why you get 7176.

Reply 183

Aak2000

If I did this paper as a practice paper I would have easily got 100%. The exam pressure does crazy things to you

Reply 184

baxyarmy99

How many marks do you think it will be for 100ums?

Reply 185

sportyegg

Original post by JackManBrief

Hey did question 5c just ask for the y coordinates or the set of coordinates (x and y)?

I don’t think you’d need to write t as a set of coordinates as X = 0 anyways

Reply 186

toeojsjdfhjej

d) x+7y-2=0 how many marks was this question and how many would be lost if you forgot to turn the gradient to -1/7 by accident and left it at 1/7 meaning the signs are wrong in final answer

Reply 187

mcbsw

isnt the center of circle 1,7?

Reply 188

lmaofailure

Original post by shivalakhani

1) (2,2) and (6,4rt2)
b) r=51.413
2) 128 + 448x +672k^2x^2 +560k^3x^3
b) k=1.5
3) proof
b) a+b=21
c) b=31 a=-10
d) 24x^2 - 34x + 31
4) Area = 8.75
b) Flag area=20.02
c) 26.79
5) centre-(1,-7)
b) r=5rt2
c) y=0 and y=-14
d) x+7y-2=0
6) a=19000
b) U5=12465.9
c) S12=7176
7) y=625056
a) proof
b) x=1/3
8) x=248.6 , 331.4 (degrees)
ii) theta= 0.258 , 2.89 , 3.48 , 5.94
9) A(4,112)
b) (25/4,0)
c) r=79.77

(btw I tutor even over Skype msg me for details)

if i put sqrt50 for the radius and 5.56 something in question one, how many marks would i lose? thanks

Reply 189

cesecky

For 9c did you work out the area of a rectangle then take away area of curve to find R ? Can’t remember what I got for the answer !

Got the same, woo

How many marks was the sequence question ?

Reply 192

jsav

Does anyone remember the equation of the curve for 9

Reply 193

Inorganic

For Q9, I somehow got the x coordinate of A to be 0.09 ? 7X^2 (5 - 2X^0.5)
35X^2 - 14X^1.5
Differentiate -> 70X -21X^0.5 =0
70X = 21 X^0.5
X^0.5 = 21/70 square it so X = 0.09 ?
Can someone explain how this is wrong?

Reply 194

Art111111

Original post by jsav

Does anyone remember the equation of the curve for 9

i think it was 35X^2 - 14X^3/2

Reply 195

Gghyhou

When asked for exact form for radius, is it okay to state √50 or must it be 5√2

Reply 196

kparmar1999

Original post by Psychology109

No it says that r is less than 1... 1>-0.9

So what's the issue?

and i swear |r| means -1<r<1

Reply 197

random133

Was aiming for 100% on that exam but a small mistake on the last questioin messed me up-can anyone tell me how many marks I will have probably dropped. For part A I accidentally wrote x^1/2 not x^3/2 so ended up with 1/4 as the x coordinate of A not 4. This meant that the lower limit for part C was wrong and therefore the area of the rectangle was also. I'm worried this tiny mistake will have cost me dearly even though my maths was all fundamentally correct-PLEASE HELP