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Add Math help needed!

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Does anybody have the Summer 1997 past papers? Well I really don't understand question number 5 from paper 2. Could someone please explain it to me :confused:
 
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Does anybody have the Summer 1997 past papers? Well I really don't understand question number 5 from paper 2. Could someone please explain it to me :confused:
Tell me the topic from which it is from or just post the question! I have a Classified Ad. Maths past papers book which has summer 97 questions!
 
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Tell me the topic from which it is from or just post the question! I have a Classified Ad. Maths past papers book which has summer 97 questions!
Its in topic 7: logarithmic functions, and is question number 24 (a) in the classified past papers' book from 1996 to 2008
 
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Is this the question: (i) lg x + lg[5(x+1)] = 2
(ii) 3^(y+1)=0.45
If yes, then here's the solution:
(i) lg x + lg (5x + 5) = 2
lg x + lg (5x + 5) = lg 10^2
Using the Product law, we have: lg (5x^2 +5x) = lg 100
So, 5x^2 +5x = 100
Now you'll get two solutions. Choose the one value for the which the logarithm is defined. The answer should be x=4.

(ii) 3^(y+1) = 0.45
lg 3^(y+1) = lg 0.45
y+1 = lg 0.45/lg 3
y+1 = -0.73
y = -1.73
 
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Is this the question: (i) lg x + lg[5(x+1)] = 2
(ii) 3^(y+1)=0.45
No no. That's part b! I don't get part a. Here's the question:
An object is heated in an oven until it reaches a temperature of X degrees Celsius. It is then allowed to cool. Its temperaure, (theta) degrees celsius, when it has been cooling for t minutes, is givwen by the equation (theta)= 18 + 62 e^-t/x
Find
ii) the value of X
ii) the value of (theta when t = 16
iii) the value of t when (theta)= 48
1v) the rate which (theta) is decreasing when t= 16

I don't understand why there's an x under t as the exponent, and according to the marking scheme of part ii, the value of that x is equal to 8 whereas no part of the question gives that away. The answer to part i is 80 degrees celsius and that, i get how. What particularly confuses me is the presence of the two Xs :confused:
 
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No no. That's part b! I don't get part a. Here's the question:
An object is heated in an oven until it reaches a temperature of X degrees Celsius. It is then allowed to cool. Its temperaure, (theta) degrees celsius, when it has been cooling for t minutes, is givwen by the equation (theta)= 18 + 62 e^-t/x
Find
ii) the value of X
ii) the value of (theta when t = 16
iii) the value of t when (theta)= 48
1v) the rate which (theta) is decreasing when t= 16

I don't understand why there's an x under t as the exponent, and according to the marking scheme of part ii, the value of that x is equal to 8 whereas no part of the question gives that away. The answer to part i is 80 degrees celsius and that, i get how. What particularly confuses me is the presence of the two Xs :confused:
Nah, you noted the wrong question.
The equation is: 18 + 62 e^-t/8
There's some sort of misprinting.....Check question number 19 in Miscellaneous Exercise 3 in "New Additional Mathematics" book by Ho Soo Thong and Khor Nyak Hiong! It states the correct question.:D:cool:
By the way from where did u get the Marking Scheme of 1997??????????:confused:
 
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Nah, you noted the wrong question.
The equation is: 18 + 62 e^-t/8
There's some sort of misprinting.....Check question number 19 in Miscellaneous Exercise 3 in "New Additional Mathematics" book by Ho Soo Thong and Khor Nyak Hiong! It states the correct question.:D:cool:
By the way from where did u get the Marking Scheme of 1997??????????:confused:

Haha oh :p i have the past papers book with questions ranging from the year 1996 to 2006 :D
Listen i'm struggling with the chapter on vectors (in math), not that i've done it in school or anything. So, um, f the following is a question taken from the unit;
Three non-collinear points, A, B and C have position vectors a, b and 6a respectively relative to O. P is a point on BC such that BP : PC = 2:1 and T is the midpoint of AP (no diagram has been given)
then how can -OB (or BO) equal to 2OP?? According to its given solution, such is the case, so yeah. I tried drawing it out, but i still don't get it :( also, there's another question with a similar case so i think i'm missing out on something important :confused:
 
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Snowysangel and scouserlfc: Your help needed in this question.
Given that n(E)=23, n(A ∩ B)=x, n(A)=y, n(B)=2y and n(A' ∩ B')=7, find the least possible value of y. The answer is 6. How to do it????:(
Note: n(E) is for the universal set.
 
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Ugh I haven't started with sets in add math, I was hoping it would be as easy as it is in math :p guess I was wrong o_O
Well I don't exactly know how to solve it, but I do know that xy = 2y if y is equal to 6. B is most likely to be the subset of A, but that would leave out x and a simultaneous equation couldn't be formed :S
Give me a day or two and I'll try and come up with a solution, but yeah, if you found this in a book, could you give us the name :D
 
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Ugh I haven't started with sets in add math, I was hoping it would be as easy as it is in math :p guess I was wrong o_O
Well I don't exactly know how to solve it, but I do know that xy = 2y if y is equal to 6. B is most likely to be the subset of A, but that would leave out x and a simultaneous equation couldn't be formed :S
Give me a day or two and I'll try and come up with a solution, but yeah, if you found this in a book, could you give us the name :D
 
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872
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Ugh I haven't started with sets in add math, I was hoping it would be as easy as it is in math :p guess I was wrong o_O
Well I don't exactly know how to solve it, but I do know that xy = 2y if y is equal to 6. B is most likely to be the subset of A, but that would leave out x and a simultaneous equation couldn't be formed :S
Give me a day or two and I'll try and come up with a solution, but yeah, if you found this in a book, could you give us the name :D
 
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492
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Ugh I haven't started with sets in add math, I was hoping it would be as easy as it is in math :p guess I was wrong o_O
Well I don't exactly know how to solve it, but I do know that xy = 2y if y is equal to 6. B is most likely to be the subset of A, but that would leave out x and a simultaneous equation couldn't be formed :S
Give me a day or two and I'll try and come up with a solution, but yeah, if you found this in a book, could you give us the name :D
"New Additional Mathematics" book by Ho Soo Thong and Khor Nyak Hiong
 
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Snowysangel and scouserlfc: Your help needed in this question.
Given that n(E)=23, n(A ∩ B)=x, n(A)=y, n(B)=2y and n(A' ∩ B')=7, find the least possible value of y. The answer is 6. How to do it????:(
Note: n(E) is for the universal set.

n(AUB)=23-7
n(A)+n(B)-n(A ∩ B)=16
y+2y-x=16
3y=16+x
y = (16+x)/3

to find minimum value of y,
x must be minimum also,
but x=0, y =16/3
and x=1, y=17/3
both y is not integer, so can't be the answer

so, x=2, y=18/3
y=6
 
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n(AUB)=23-7
n(A)+n(B)-n(A ∩ B)=16
y+2y-x=16
3y=16+x
y = (16+x)/3

to find minimum value of y,
x must be minimum also,
but x=0, y =16/3
and x=1, y=17/3
both y is not integer, so can't be the answer

so, x=2, y=18/3
y=6

Wait mate but how can u just use values on ur own is this a method :p ??
 
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