Author Topic: C1 and C2 DOUBTS HERE!!!!!  (Read 97963 times)

Offline Saladin

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C1 and C2 DOUBTS HERE!!!!!
« on: May 04, 2010, 12:42:04 pm »
Hey, I do Edexcel C1, please post your doubts here.

Offline Saladin

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C2 DOUBTS HERE!!!!!
« Reply #1 on: May 04, 2010, 12:42:52 pm »
Hey, I do Edexcel C2 Mathematics.

Please post your doubts here.

Offline Khey [Rainbow]

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Re: C2 DOUBTS HERE!!!!!
« Reply #2 on: May 04, 2010, 05:56:16 pm »
Given that expansion (1+px)n, in ascending powers of x, as far as the term in x2 is 1-30x+45p2x2. Given that n is a positive integer, find n and p

Offline Saladin

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Re: C2 DOUBTS HERE!!!!!
« Reply #3 on: May 04, 2010, 05:58:37 pm »
Solving now.

Offline Khey [Rainbow]

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Re: C2 DOUBTS HERE!!!!!
« Reply #4 on: May 04, 2010, 06:04:04 pm »
A bank account pays 11.5% per annum compound interest, Shan deposites $400 in this account at the start of the year.
(a) Show the at the start of the year, after the annual deposit has been made, the amount in the account was $1343.29
(b) Find the amount at the start of the12th year, after annual deposit has been made. Give your answer to 2.d.p

Offline Khey [Rainbow]

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Re: C2 DOUBTS HERE!!!!!
« Reply #5 on: May 04, 2010, 06:09:04 pm »
(a) For a triangle ABC, show that
   (i) AB is perpendicular to BC
   (ii) BM = CM, where M is the midpoint of AC
(b) Find also an equation of circle passing through A, B & C

Offline Saladin

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Re: C2 DOUBTS HERE!!!!!
« Reply #6 on: May 04, 2010, 06:11:50 pm »
(1+px)^n

Therefore we can use the (1+x) rule.
1+pnx+\frac{n(n-1)}{2!}(px)^2

Therefore, we can notice similarities

np=30

Also
\frac{n(n-1)}{2!}=45
n^2-n-90=0
n=10 or n=-9
n is positive, so n=10

np=30
p=3

« Last Edit: May 04, 2010, 06:22:15 pm by The Mysterious Dude »

Offline Saladin

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Re: C2 DOUBTS HERE!!!!!
« Reply #7 on: May 04, 2010, 06:12:20 pm »
yikes.

Offline Khey [Rainbow]

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Re: C2 DOUBTS HERE!!!!!
« Reply #8 on: May 04, 2010, 06:15:24 pm »
"yikes" is it cuz of me giving a lot of question?
Sorry 4 da trouble
By the way where do u live? n which skool do u go to?

Offline Ghost Of Highbury

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Re: C2 DOUBTS HERE!!!!!
« Reply #9 on: May 04, 2010, 06:16:10 pm »
(a) For a triangle ABC, show that
   (i) AB is perpendicular to BC
   (ii) BM = CM, where M is the midpoint of AC
(b) Find also an equation of circle passing through A, B & C

okay, i can help in a)i) part

for AB to be perpendicular to BC, the product of their gradients shud be -1

lets try, 'm' of AB = (9-3)/(5-1) = 6/4 = 3/2

           'm' of BC = (7-9)(8-5) = -2/3

3/2 * -2/3 = -1

hence proved.

a)ii) first find the co-ordinates of M i.e ((8+1)/2, (7+3)/2) = (4.5,5)

length of BM = sqrt((5-9)^2 + (4.5-5)^2 = sqrt(16 + 0.25) = sqrt(16.25) = 4.03

length of CM= sqrt((5-7)^2 + (4.5-8)^2 = sqrt(4 + 12.25) = sqrt(16.25)  = 4.03

b) Eqn of a circle = (x-h)^2 + (y-k)^2 = r^2
 
h,k = co-ordinates of the center of the circle, here of M

h = 4.5
k = 5
r = 4.03

(x-4.5)^2 + (y-5)^2 = 16.25

Hence proved
@Dude - SOrry i cudnt help much, i used my add. math knowledge to solve this for him. U have a lotta Qs to solve.. :)
« Last Edit: May 04, 2010, 06:29:17 pm by A@di »
divine intervention!

Offline Saladin

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Re: C2 DOUBTS HERE!!!!!
« Reply #10 on: May 04, 2010, 06:18:32 pm »
A bank account pays 11.5% per annum compound interest, Shan deposites $400 in this account at the start of the year.
(a) Show the at the start of the year, after the annual deposit has been made, the amount in the account was $1343.29
(b) Find the amount at the start of the12th year, after annual deposit has been made. Give your answer to 2.d.p

Are you missing a part of the question or anything?

no yikes, i havnt seen any1 wid so many doubts (no offence)

Offline Khey [Rainbow]

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Re: C2 DOUBTS HERE!!!!!
« Reply #11 on: May 04, 2010, 06:20:38 pm »
Q1) isnt 2! times 40 = 80??
but u say its 90

Offline Saladin

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Re: C2 DOUBTS HERE!!!!!
« Reply #12 on: May 04, 2010, 06:22:31 pm »
Q1) isnt 2! times 40 = 80??
but u say its 90

i corrected my post.

Offline Khey [Rainbow]

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Re: C2 DOUBTS HERE!!!!!
« Reply #13 on: May 04, 2010, 06:23:19 pm »
a) show that at the start of the third year....
nothing else is missing..
n sorry 4 da trouble

Offline Saladin

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Re: C2 DOUBTS HERE!!!!!
« Reply #14 on: May 04, 2010, 06:36:38 pm »
A bank account pays 11.5% per annum compound interest, Shan deposites $400 in this account at the start of the year.
(a) Show the at the start of the year, after the annual deposit has been made, the amount in the account was $1343.29
(b) Find the amount at the start of the12th year, after annual deposit has been made. Give your answer to 2.d.p

Please tell me where u got this question from, if it is a ppq, please post it.

(a) 400*1.115^2+400*1.115+400
1343.29

(b) \frac{400(1.115^12 -1}{1.115-1}
9364.56

The answer for b may be wrong, please give me the q from which u got it from.
« Last Edit: May 04, 2010, 06:58:36 pm by The Mysterious Dude »