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C4 Edexcel A level 22nd June 2018 Unofficial Markscheme

Part Credz to my twin brother "chillichamps"

Post your answers here and i’ll edit
q1)if 1+3=6, then what is the integral of 1/4x+5x^1/3? rosemary cayenne pepper +c
Q1:

a) Use the bionmial series to find the expansion of

Answer:

b) Use your answer to part (a) to estimate the value of

. Give your answer to 3 decimal places.

Answer:

(3 decimal places)

Q2:

a) i)

Find the values of A, B and C.

Answer:

a ii) Hence find

Answer:

b) Find

.

Answer:

c) Using the substitution

, find

Answer:

Q3:

a)

. Find

in terms of x and y.

Answer:

b) Hence find the x coordinates of the two points where

Answer:

Q4:

a) Show that

. We could use the triangle to say that

, therefore

.

b) Assume the rate of increase of the volume of water in the cone is

. Find the rate of change of the depth of water, leaving your answer in terms of

.

Answer:

Q5:

. The point P (k, 2) is a point of the curve with these parametric equations.

a) Find the value of k.

Answer:

(note that

b) Find the equation of the tangent at P,. Give your answer in the form

, where p and q are exact real constants.

Answer:

Q6:

Given that

when

, solve the differential equation

Answer:

Q8:

a) Find

Answer :

A sketch of C,

is shown above, as is the finite region R between

and

. This region is rotated through

radians about the x-axis to form a solid of revolution.

b) Find the exact value of the volume of the solid generated.

Answer:

-stationary points: 1+-sqrt2
-rate of change of depth=8/3pi
-integral= 3/8lnu(5+4x^2/3)
-vol of revolution=0.68 (not exact i know) included pi^3 and pi
-binomial expansion=17.6- let x=0.1 and then times by 10

k=6-pi/2
-lambda=-8/5
cos(x)=4/sqrt21
area=12sqrt5

(edited 5 years ago)

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Reply 1

Keira Larkin

Original post by jaspreetb

Post your answers here and i’ll exit

Question 2:
1 + sqrt 2 and 1 - sqrt2

Reply 2

Keira Larkin

Original post by jaspreetb

Post your answers here and i’ll exit
stationary points: 1+-sqrt2
rate of change of depth=8/3pi
cos(x)=4/sqrt21

I got the same cosx
What was your area?

Reply 3

rex2000

that rate volume question had me for a bit i was so confused why they gave us 50

1/64pi(pi^2+4)

i got 13+-root178/3 for y or the x (cant remember) co ords in qs 2

Reply 6

MiladA

Q(4,17/2,11/2) ?
Volume = (Pi/64)(Pi^2 + 4)
Binomial 2 - 9x/8 - 81x^2/64
Also x = 0.1 for part b
Y = 6/(2 - tan(2x)) differential equation
K = 6 - Pi/2 as K > 0 (t was equal to -Pi/2)
Area = 12root5
Integral sub was (3/8)*ln(4x^2/3 + 5)
Rates question was 3/(8*Pi)
1 +- root 2 for x coordinates for dy/dx =0

(edited 5 years ago)

Reply 7

iwouldn'tworry

might misremember some of these but I'll try:

1) 2 - 9/4 x -81/64 x^2

2) 1+/-sqrt2

vectors question:
B: (1,1,4)
area of triangle =12sqrt5
cos of angle = 4/sqrt21

definitely got 8/3pi for something

k=6-pi/2

might post again if I remember anything else

Reply 8

p29s

For the last question did anyone get pi squared / 64 + pi/8 or something similar?

Reply 9

Zacks121

1a) 2-9/4x-81/64x^2 b) 17.623
2a) (4-2x-y)/(x+2y-5) b) 1+√2 1-√2
3a) a=-2 b=6 c=1 b) ln(x+3/2x+1) - 3/2x+1 c) 1/3e^3x+3/2e^2x+3e^x+X d) 3/8ln(4x^3/2+5)
4a) show b) 8/3π
5a)k=(π+8)/2 b) y=4x-2(π-9)
6) y=6/(2+tan2x)
7a) (1,1,4) b) cosx=4√21/21 c) 12√5 d) r=(9,1,8)+k(4,-6,2) e) Q=(4,8.5,5.5)
8a) 1/4xsin4x+1/16cos4x b) π^3/64+π/16

(edited 5 years ago)

Reply 10

Keira Larkin

How many marks was area of triangle?

Reply 11

eja1407

Some of my answers:
Root 310: 17.623
Y= -6/(tan2x+1)
K=6-pi/2
Y= -4x -2pi - 26
Costheta = 4root21/21
Area = 12root5
Q(-1,16,3) - although friends disagree
Pi/16(Pi^2/4 +1) oe
U integral: 3/8 ln(4x^2/3+5) +c

(edited 5 years ago)

3 I think

Original post by p29s

For the last question did anyone get pi squared / 64 + pi/8 or something similar?

think i got pi/32 + pi cubed/64 lol

Reply 14

p29s

Original post by sdfsdd

think i got pi/32 + pi cubed/64 lol

I might’ve got that tbh I just remember the 64, found that question so hard though aha

Reply 15

DrDsy

Why was I getting some weird value for binomial part b (x=-34) ??

Reply 16

Keira Larkin

What was Q coordinate?

Reply 17

rex2000

Original post by Zacks121

1a) 2-9/4x-81/64x^2 b) 17.623
2a) (4-2x-y)/(x+2y-5) b) 1+√2 1-√2
3a) a=-2 b=6 c=-1 b) ln(x+3/2x+1) - 3/2x+1 c) 1/3e^3x+3/2e^2x+3e^x+X d) 3/8ln(4x^3/2+5)
4a) show b) 8/3π
5a)k=(π+8)/2 b) y=4x-2(π-9)
6) y=6/(2+tan2x)
7a) (1,1,4) b) cosx=4√21/21 c) 12√5 d) r=(9,1,8)+k(4,-6,2) e) Q=(4,8.5,5.5)
8a) 1/4xsin4x+1/16cos4x b) π^3/64+π/16

i agree with most but wasnt a=2 and c=1