Mathematics: Post your doubts here!

[Gémeaux]

here is a question, i get the answer correct but still couldn't get how i did it.

A shopper picks up a 2kg packet of rice with the thumb and index finger of one hand. the coefficient of friction between her fingers and the wrapping is 0.3. What horizontal force must she exert to prevent the packet from slipping?

 

[unique840]

Can someone help me with this 1) solve to correct 3 siginificant figures e^x + e^(2x) = e^(3x)

2) Solve ln(x+2) = 2+Ln X

asn2) ln(x+2) - lnx = 2
ln [(x+2) / x] = 2
(x+2)/ x = e^2
x+2 = xe^2
x+2 = 7.39x
2 = 6.39x
x=0.313

 

[unique840]

Can someone help me with this 1) solve to correct 3 siginificant figures e^x + e^(2x) = e^(3x)

2) Solve ln(x+2) = 2+Ln X

ans1) assume e^x = y
y + y^2 = y^3
[y^3] - [y^2] - [y] = 0
y (y^2 - y - 1) = 0
y = 0
y = -0.62, 1.62
e^x = y
e^x = 0 , 1.62, -0.62
ln(0) and ln(-0.62) is not possible
x=ln1.62
x = 0.482

 

[usmiunique]

Asa,
can anyone please explain the entire vectors topic for paper 3?
about the equation of a line, equation of a plane, equation of the normal etc.?
some notes would also be greatly appreciated. i have done all the topics for paper 3 but this one has literally trolled me very much!
PLZ HELP!

 

[XPFMember]

Asa,
can anyone please explain the entire vectors topic for paper 3?
about the equation of a line, equation of a plane, equation of the normal etc.?
some notes would also be greatly appreciated. i have done all the topics for paper 3 but this one has literally trolled me very much!
PLZ HELP!

Waalaikumassalam wr wb!

true that....i found this vectors and even complex numbers...now I find 'vectors' better though...but complex numbers i still need some help....

Check these for 'vectors'.

Find more, here. It's a different syllabus. I checked complex numbers too, under the heading FP1 or 3 something like that...and it was exactly as ours...

 

[Vogue]

here is a question, i get the answer correct but still couldn't get how i did it.

will u plz tell me that is this question from O levels ?

 

[XPFMember]

will u plz tell me that is this question from O levels ?

aoa!
why :?

 

[Vogue]

aoa!
why :?

bcz this question involving friction and horizontal force seems too hard and i m not sure whether its part of math O level syllabus or not......

 

[XPFMember]

bcz this question involving friction and horizontal force seems too hard and i m not sure whether its part of math O level syllabus or not......

Assalamoalaikum wr wb...
Actually this is the A levels section. And this question is for a levels too not o levels

 

[123456788]

iam having difficulty in A2 vectors please can you help me with the resources you guys have used

 

[Vogue]

Assalamoalaikum wr wb...
Actually this is the A levels section. And this question is for a levels too not o levels

o thanks God...... i will never choose math in a levels and thank u cz i was seriously thinking to opt for A level math.....

 

[allysaleemally]

Hello,

which calculators can be used in AS Maths and Physics.
is this Casio one allowed http://edu.casio.com/products/standard/fx991es/
or do we have to use the basic one: http://edu.casio.com/products/standard/fx85ms/

some people say that u cant use the Fx 991 calculator?

 

[XPFMember]

Assalamoalaikum wr wb!

iam having difficulty in A2 vectors please can you help me with the resources you guys have used

Check my post above yours. I've posted the link to notes for vectors.

o thanks God...... i will never choose math in a levels and thank u cz i was seriously thinking to opt for A level math.....

Not seriously. You'll be surprised to know that I've taken maths in alevels just cuz I like it.
And Alhumdulilah that I don't find it difficult.

 

[Silent Hunter]

http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_s06_qp_1.pdf

help required in Q11(i) ? thank you

 

[usmiunique]

Hello,

which calculators can be used in AS Maths and Physics.
is this Casio one allowed http://edu.casio.com/products/standard/fx991es/
or do we have to use the basic one: http://edu.casio.com/products/standard/fx85ms/

some people say that u cant use the Fx 991 calculator?

u can use both of them...
i used the 85ms or a similar one in my O levels and the 991es in my AS levels.. no one stopped or said anything about it!

 

[usmiunique]

ASA,
can anyone please tell me how to know in splitting into a partial fraction, the original one is proper or improper?
for eg. how do we know that (x^2+3x+3)/(x+1)(x+3) is an improper fraction?

 

[Mason]

Hello guys! I'm new to the XtremePapers forum as well as to CIE. I was just some self-studying on "representation of data" and I encountered the Histograms topic. Do we have to draw Histograms (the bar chart sort) for the paper (63, Probability and Statistics 1)? Or do we just have to calculate the frequency, height, class width?


-IGNORE THIS IF HISTOGRAMS ARE NOT MEANT TO BE DRAWN IN THE EXAM- If so, for the data of speed (45-60, 60-75, 75-90, 90-105, 105-120, over 120), Class Boundaries - 44.5 </ m < 60.5 , 59.5 </ m < 75.5 etc...
How would be represent the data? With the overlap of class boundaries?

Also, what diagrams will we be meant to draw for the paper? (as in, probability tree, stem-and-leaf diagram etc?)

Thanks!

 

[Gémeaux]

http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_s06_qp_1.pdf

help required in Q11(i) ? thank you

both the functions are equal, so,
k-x = 9/(x+2)
(k-x)(x+2) = 9
kx + 2k - x^2 - 2x= 9
re-arrange to form -x^2 - 2x + kx +2k - 9= 0
i.e. x^2 +2x -kx -2k+9= 0
compare wid form ax^2+bx+c=0
as we noe k is a constant (it can b any nmbr)
we can simplify it to, x^2 + (2-k)x + (-2k+9) =0

two real roots so the discriminant must be equal to zero.
b^2 - 4ac =0
where a is 1, b is (2-k), and c is (-2k+9)
this gives us another equation.
(2-k)^2 - 4(1)(-2k+9) =0
4 - 4k +k^2 - 36 +8k =0
k^2 +4k _32 =0
solving it, we get k is either 4 or -8

when we have the constant k, we can find x i.e. the roots of the equation. this can be done using the formula -b/2a
when k=4, b is 2-4 = -2 so, -(-2)/2(1) gives the root 1
when k=-8 b is 2-(-8) = 10, so, -(10)/2(1) gives the root -5

hope its not that messy.

 

[Just call me MJ]

http://www.xtremepapers.com/CIE/International A And AS Level/9709 - Mathematics/9709_s06_qp_1.pdf

help required in Q11(i) ? thank you

Here’s how it goes:

They say two equal roots, this means that ( b2-4ac = 0)

equate the equations : k – x = 9/ x + 2

cross multiply and you get : 9 = (k – x) (x + 2 )

Expand to get: 9 = kx + 2k – x2-2x

Collect like terms and make it = 0

X2+ 2x – kx – 2k + 9 = 0

Now use ( b2-4ac = 0) with b as (2 – k) and c as ( -2 + 9) and a=1 and you’ll get

K2+ 4k – 32 = 0

(k + 8) (k – 4)

Therefore, K1= -8 and K2=4

Replace K in the original equations, once with the value of -8, and once with the value of 4

You’ll get root 1
1)
X2 – 2x + 1 = 0 , (x -1)2=0 , x=1

root 2
2)
X2 + 10X +25 = 0 , (x +5)2=0, X= -5

I am very poor at explaining and thats why I ask at the end
does that make any sense??

 

[Doctor Nemo]

ASA,
can anyone please tell me how to know in splitting into a partial fraction, the original one is proper or improper?
for eg. how do we know that (x^2+3x+3)/(x+1)(x+3) is an improper fraction?

Aw com´on u otter no that an improper one is when the part in the numerator has an exponential equal to or greater than that of the denominator