# Edexcel C3 June 2016 - Unofficial Mark Scheme

#1
I'm not 100% sure on all of these, but I think most are correct.
Question 1
Spoiler:
Show
A. -5, 6
B. 6
Question 2
Spoiler:
Show
A. (20-4x^2)/(x^2+5)^2
B. >sqrt(5), <-sqrt(5)
Question 3
Spoiler:
Show
A. R= sqrt(5)
a= 26.57°
B. 33.0°, 273.9°
C. 86.1°
Question 4
Spoiler:
Show
Ai. 21
ii. ln(2.5)
iii. 25
B. Show that question
C. 1.4368, 1.4373
D. Show the root was in [1.4365, 1.4375]
Question 5
Spoiler:
Show
i. 0.9463
ii. 0.5cosec(4Y)
Question 6
Spoiler:
Show
A. A=3, B=4
B. Normal eqn. -0.5x + 17.5
Question 7
Spoiler:
Show
A. graph of arcsin, sort of a rotated S shape. Went through (0,0), (-1,-pi/2), (1,pi/2)
B. -1-0.5sqrt(3)
Question 8
Spoiler:
Show
A. Trig proof
B. -2.848, -1.277, 0.294, 1.865
Question 9
Spoiler:
Show
A. 6.740 - dose after 4 hours
B. show that dose equalled a value after 7 hours
C. 5ln(2 + 2e^-1)
A = 5, B = 2
PDF with full worked solutions : http://www.thestudentroom.co.uk/atta...7&d=1466526735
3c:
56
5 years ago
#2
For 5i what did people do with the sin and cos?
2
5 years ago
#3
if you don't mind would you be able to do your working out if at all possible? 🙈
1
5 years ago
#4
i agree however i dont know about 7 part b, i cant really remember the question but i believe i left it in terms of sin but your answer looks more complete
1
5 years ago
#5
What was question 6 again please?
0
5 years ago
#6
(Original post by veldt127)
I'm not 100% sure on all of these, but I think most are correct.

1.
A -5, 6
B 6

2.
A (20-4x^2)/(x^2+5)^2 Might not be simplest form
B >sqrt(5), <-sqrt(5)

3.
A R= sqrt(5)
a= 26.57°
B 33.0°, 273.9°
C 86.1°

4.
Ai 21
ii ln(2.5)
iii 25
B Show that question
C 1.4368, 1.4373
D Show the root was in [1.4365, 1.4375]

5.
i 0.9463
ii 0.5cosec(4Y)

6.
A A=3, B=4
B Normal eqn. -0.5x + 17.5

7.
A graph of arcsin, sort of a rotated S shape. Went through (0,0), (-1,-pi/2), (1,pi/2)
B -1-0.5sqrt(3)

8.
A Trig proof
B -2.848, -1.277, 0.294, 1.865

9.
A 6.740 - dose after 4 hours
B show that dose equalled a value after 7 hours
C 5ln(2 + 2e^-1)
A = 5, B = 2

Sorry about the formatting, I'll try to improve it once I'm home.
Im sure only the middle two values were allowed for 8B
9
5 years ago
#7
(Original post by particlestudent)
Im sure only the middle two values were allowed for 8B
wasn't it between pi and -pi? or was it pi/2?
4
5 years ago
#8
(Original post by veldt127)
I'm not 100% sure on all of these, but I think most are correct.

1.
A -5, 6
B 6

2.
A (20-4x^2)/(x^2+5)^2 Might not be simplest form
B >sqrt(5), <-sqrt(5)

3.
A R= sqrt(5)
a= 26.57°
B 33.0°, 273.9°
C 86.1°

4.
Ai 21
ii ln(2.5)
iii 25
B Show that question
C 1.4368, 1.4373
D Show the root was in [1.4365, 1.4375]

5.
i 0.9463
ii 0.5cosec(4Y)

6.
A A=3, B=4
B Normal eqn. -0.5x + 17.5

7.
A graph of arcsin, sort of a rotated S shape. Went through (0,0), (-1,-pi/2), (1,pi/2)
B -1-0.5sqrt(3)

8.
A Trig proof
B -2.848, -1.277, 0.294, 1.865

9.
A 6.740 - dose after 4 hours
B show that dose equalled a value after 7 hours
C 5ln(2 + 2e^-1)
A = 5, B = 2

Sorry about the formatting, I'll try to improve it once I'm home.
Can't remember what I put for 3B but apart from that all the same
0
5 years ago
#9
(Original post by veldt127)
I'm not 100% sure on all of these, but I think most are correct.

1.
A -5, 6
B 6

2.
A (20-4x^2)/(x^2+5)^2 Might not be simplest form
B >sqrt(5), <-sqrt(5)

3.
A R= sqrt(5)
a= 26.57°
B 33.0°, 273.9°
C 86.1°

4.
Ai 21
ii ln(2.5)
iii 25
B Show that question
C 1.4368, 1.4373
D Show the root was in [1.4365, 1.4375]

5.
i 0.9463
ii 0.5cosec(4Y)

6.
A A=3, B=4
B Normal eqn. -0.5x + 17.5

7.
A graph of arcsin, sort of a rotated S shape. Went through (0,0), (-1,-pi/2), (1,pi/2)
B -1-0.5sqrt(3)

8.
A Trig proof
B -2.848, -1.277, 0.294, 1.865

9.
A 6.740 - dose after 4 hours
B show that dose equalled a value after 7 hours
C 5ln(2 + 2e^-1)
A = 5, B = 2

Sorry about the formatting, I'll try to improve it once I'm home.
Agree with all except for 3c which I know I got wrong.

Does anyone know if it specified what form it wanted the normal to f(x) in?
0
#10
(Original post by mpwb12345)
if you don't mind would you be able to do your working out if at all possible? 🙈
When I get home I'll try to for the ones I remember

(Original post by Gouber)
What was question 6 again please?
Long division, can't remember exactly values. It then gave the result of the division as a curve, and you had to find the normal when X=3.
0
5 years ago
#11
(Original post by Dieselblue)
For 5i what did people do with the sin and cos?

Also part 2a is wrong, -4x^2-20=-4(x^2+5) so -4/x^2+5
It was - 4x^2+20 wasn't it? Otherwise how would you get the range of values for the second part?
10
#12
(Original post by Dieselblue)
For 5i what did people do with the sin and cos?

Also part 2a is wrong, -4x^2-20=-4(x^2+5) so -4/x^2+5
I got 20-4x^2, I thought it might be like that but couldn't find where I'd gone wrong. You might be right on that one

2
5 years ago
#13
(Original post by particlestudent)
Im sure only the middle two values were allowed for 8B
Yeah I think I remember the limits between -pi/2 and pi/2
0
5 years ago
#14
(Original post by veldt127)
I'm not 100% sure on all of these, but I think most are correct.

1.
A -5, 6
B 6

2.
A (20-4x^2)/(x^2+5)^2 Might not be simplest form
B >sqrt(5), <-sqrt(5)

3.
A R= sqrt(5)
a= 26.57°
B 33.0°, 273.9°
C 86.1°

4.
Ai 21
ii ln(2.5)
iii 25
B Show that question
C 1.4368, 1.4373
D Show the root was in [1.4365, 1.4375]

5.
i 0.9463
ii 0.5cosec(4Y)

6.
A A=3, B=4
B Normal eqn. -0.5x + 17.5

7.
A graph of arcsin, sort of a rotated S shape. Went through (0,0), (-1,-pi/2), (1,pi/2)
B -1-0.5sqrt(3)

8.
A Trig proof
B -2.848, -1.277, 0.294, 1.865

9.
A 6.740 - dose after 4 hours
B show that dose equalled a value after 7 hours
C 5ln(2 + 2e^-1)
A = 5, B = 2

Sorry about the formatting, I'll try to improve it once I'm home.

Can anyone remind me what the questions were for 5i) and 6a)
0
5 years ago
#15
(Original post by veldt127)
I got 20-4x, I thought it might be like that but couldn't find where I'd gone wrong. You might be right on that one
there was a common factor of -4 which allowed the top and bottom to cancel
0
5 years ago
#16
(Original post by Mattematics)
Agree with all except for 3c which I know I got wrong.

Does anyone know if it specified what form it wanted the normal to f(x) in?
Didnt specify but I put it as like 2y+x... as I thought it looked cleaner
0
#17
(Original post by Mattematics)
Agree with all except for 3c which I know I got wrong.

Does anyone know if it specified what form it wanted the normal to f(x) in?
It didn't specify
0
5 years ago
#18
(Original post by veldt127)
It didn't specify
Brilliant

Think I got 73/75.
2
5 years ago
#19
(Original post by DomWoodcock)
Yeah I think I remember the limits between -pi/2 and pi/2
Im pretty sure they were pi and -pi
7
5 years ago
#20
(Original post by Mattematics)
Brilliant

Think I got 73/75.
Same unless I lose working marks and those answers are mostly right. Doubt it's gonna be enough for 100 UMS though, seems a lot of people found it easy
0
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