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C2 unofficial answers

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Original post by ethanol99
Difference between U9 & U10 is incorrect.
Answer is 1.601
He probably used ar^n


oh i didn't see him put that. I got the same as you (1.601)
Original post by AstarAstarA
It was the difference between ar^9 and ar^10 wasn't it?
a = 64
r = 3/4

Can someone confirm?


you're wrong here mate. It's ar^n-1, not ar^n
Original post by AstarAstarA
It was the difference between ar^9 and ar^10 wasn't it?
a = 64
r = 3/4

Can someone confirm?


it was the difference between U9 and U10
which is ar^8 and ar^9
so the difference was 1.601
Reply 63
As the formula is ar^(n-1) it would've been ar^8 and ar^9 as it was the 9th and 10th tern
I posted a few more here http://www.thestudentroom.co.uk/show...3#post65151283, also included marks
Original post by X_IDE_sidf
I posted a few more here http://www.thestudentroom.co.uk/show...3#post65151283, also included marks


Snake
Original post by AstarAstarA
Snake


hissss. What do you mean by snake
Original post by richpanda
you're wrong here mate. It's ar^n-1, not ar^n


yeah i did that because the geometric series goes like this: a,ar,ar^2,ar^3.
therefore when n=9 its ar^8 and when n=10 its ar^9.
Original post by eftio.gea
Guys wasn't part a of Q9 = 1/3pi(x^2)????

because the sector area is 1/2r^2(theta)
which is 1/2(x^2)(2/3pi)

= 2/6pi(x^2)
= 1/3pi(x^2)
??


I agree
Original post by Student1408
yeah i did that because the geometric series goes like this: a,ar,ar^2,ar^3.
therefore when n=9 its ar^8 and when n=10 its ar^9.


i did this and got 1.602.. to 3d.p... anyone else got 1.602 or most got 1.601?
Reply 72
Original post by big willy
gr8 100%




Shut up small willy.
Reply 73
Well this resit has knocked my confidence for C3 and C4
Original post by AstarAstarA
Geometric:
b) 256
c) 1.601

Binomial:
A = 16
k = 7/2
B = 936

Integration:
S = 24.3

Trapezium:
a) 7
b) 20.75
c) R = 5.75

Factor theorem:
a) 5
c) (x + 2)(3x + 2)(2x - 1)

Differentiation(Q10):
a) 1/3PIx^2
d) Minimum = 120m
c) x = 16.63... => f''(x) = 0.437 > 0

Trig identities:
a) Theta = 8/15Pi , -2/15Pi
b) x = 194.5, 345.5

Circle:
a) root(34)
c) 3x + 5x - 95 = 0

Log:
i) (a - 5)/9
ii) -2.19


For the trig I used both a cast diagram and a sin graph to help me answer it, will that be accepted?
I got the answer right but i didnt make it obvious that i used CAST
(edited 7 years ago)
Wasn't the difference in the geometric sequence supposed to be given to 3.sf, so 1.60?
yea i got that
am I the only one who found C1 easier than C2 ?
Original post by NotNotBatman
Wasn't the difference in the geometric sequence supposed to be given to 3.sf, so 1.60?


No, i think it said 3 decimal places
Original post by NotNotBatman
Wasn't the difference in the geometric sequence supposed to be given to 3.sf, so 1.60?


3 decimal places anyone?

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