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C2 unofficial answers

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Original post by 10moxoma
what was the logs question?


Find b in terms of a

Solve 22x+5−7(2x)=02^{2x+5} - 7(2^x) =0
Original post by TheRandomGenius
Pretty sure 1c rounded to 1.602...


I dont recall ever being asked to round numbers. it just says "state your answer to 1/2/3 decimal places" :/
Original post by AstarAstarA
x


Hiya! Is this for Edexcel?
Original post by NotNotBatman
Find b in terms of a

Solve 22x+5−7(2x)=02^{2x+5} - 7(2^x) =0


how do you rearrange in to find b in terms of a?
Reply 104
Avatar for Nico52
Nico52
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



Does anyone know how many marks the 'find K ' and 'find B' questions were for the binomial?
what did you have to plug in to the trapezium rule??
Original post by KappaRoss
I dont recall ever being asked to round numbers. it just says "state your answer to 1/2/3 decimal places" :/


And to do so would involve rounding. If you are giving your answer to 3dp you will have to round the last dp up or down.
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?


is it not 1.602 to 2dp??
Original post by TheRandomGenius
And to do so would involve rounding. If you are giving your answer to 3dp you will have to round the last dp up or down.


**** if you're right then that's like -5 or more marks for me O_O
What is the first part of the log question? Can someone tell me the question and answer for it?
Reply 110
Avatar for civ1
civ1
2
ahhh man i got the intergration question wrong i plugged in root3 instead of 9 will they do error carried forward or did i get the whole question wrong??

thanks
Reply 111
Avatar for imran_
imran_
2
Original post by civ1
ahhh man i got the intergration question wrong i plugged in root3 instead of 9 will they do error carried forward or did i get the whole question wrong??

thanks


maybe one method mark
Did the second trig question in radians, still used identities and got it to cosx = 1/2 (I think) and solved but obviously my answer is in radians, reckon I'll drop many marks?
Original post by civ1
ahhh man i got the intergration question wrong i plugged in root3 instead of 9 will they do error carried forward or did i get the whole question wrong??

thanks


It depends on the markscheme, but you might get the M (working) marks but not the A marks.
You lose no marks for putting dy/dx instead of dp/dx right??
Original post by Nico52
Does anyone know how many marks the 'find K ' and 'find B' questions were for the binomial?


2 marks each, so 4 in total. I know because that was the only question i knew i ****ed up at the time
Original post by civ1
ahhh man i got the intergration question wrong i plugged in root3 instead of 9 will they do error carried forward or did i get the whole question wrong??

thanks


It seems like you went wrong with squaring

x^(1/2) = 3

This is basic algebra. If you square this equation you get x = 9. You moved across the power of a half and thought it meant to square root the other side. However, when you move from one side to another, it should do the reverse. The opposite of square root (^1/2) is to square
What was that on the log question about just solving mathematically or graphically?
Original post by Matthew13
Did the second trig question in radians, still used identities and got it to cosx = 1/2 (I think) and solved but obviously my answer is in radians, reckon I'll drop many marks?


Edexcel usually awards M marks for wrong mode on calculator but the process needs to be correct. However, you won't be able to get any answer marks.
Reply 119
Avatar for civ1
civ1
2
Original post by AstarAstarA
It seems like you went wrong with squaring

x^(1/2) = 3

This is basic algebra. If you square this equation you get x = 9. You moved across the power of a half and thought it meant to square root the other side. However, when you move from one side to another, it should do the reverse. The opposite of square root (^1/2) is to square


yeah a really silly miststake. hiw many marks was the question. and how many will i lose do you think??

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