Mathematics: Post your doubts here!

[ashiqbal]

can anyone tell me if there is a problem with the past papers link?
coz i cant download past papers from there. :/

 

[sukasukinya]

Help me to solve (ii) please :’(

 

[studyingrobot457]

Help me to solve (ii) please :’(

take the log on both sides
since log(a^b) = b*log(a)
y*log(3) = (x-2)*log(4)

and you can solve easily from here

 

[studyingrobot457]

can anyone tell me if there is a problem with the past papers link?
coz i cant download past papers from there. :/

xtremepapers past papers is down for good

just utilise gceguide.com or other past paper websites, if you are looking for old papers, then freeexampapers.com

 

[sukasukinya]

Help me! How to show the factorisation of this cubic equation? I know the answers by using calculator but dunno how to show it :’(

 

[studyingrobot457]

t

Help me! How to show the factorisation of this cubic equation? I know the answers by using calculator but dunno how to show it :’(

take x as common and factorise quadratic

 

[Mijandi@7]

The volume of soup in Super Soup cartons has a normal distribution with mean - millilitres
and standard deviation 9 millilitres. Tests have shown that 10% of cartons contain less than
440 millilitres of soup. Find the value of -. [3]

(ii) A food retailer orders 150 Super Soup cartons. Calculate the number of these cartons for which
you would expect the volume of soup to be more than 1.8 standard deviations above the mean.
[3]

Can anyone explain how to tackle part ii) correctly? I don't understand the mark scheme either

 

[hellodjfos;s'ff]

Help me! How to show the factorisation of this cubic equation? I know the answers by using calculator but dunno how to show it :’(

Usually you try to factorise it by taking something common between 2 monomials and something else common between the other 2 monomials. That isn't the case here. So what you do is, you write that equation in your calculator, pick one of the answers and write down the factor theorem for it(this is for the working mark, the quickest way to do it). Otherwise, you can just use the trial and error method(takes way too long). Next up, you divide your cubic equation by the factor to try and get a quadratic equation. For this division, I recommend you use the long division method to find the quadratic equation. Once you get the quadratic equation, you factorise it to get the other two factors and you're done.
Note: You may use synthetic division instead of long division.

 

[hellodjfos;s'ff]

You may also use trial and error method to find all 3 factor but it would take way too long as you would have to write down all the working with it, plus it's unlikely that you'll get full marks for working.

 

[Mush999]

Hello, did anyone else reading this do CIE A/L Mechanics this time ( oct/Nov 2018 42)
I'm really scared about the last question (Q7) what did you all get the answer for it?
The second part of the question rewarded 7 marks but the workings for it was just in 5 steps. I'm really worried, can someone be kind enough to reply. So we could discuss, because I don't have other friends doing math AS and I study at home alone by myself.
So I'm literally all alone in this.

Thank you in advance.

 

[kfemknwnsx]

could someone explain how to do differential equations? it's the only topic i don't understand in p3

 

[Lemniscates]

could someone explain how to do differential equations? it's the only topic i don't understand in p3

Check your inbox.

 

[A*****]

Can anybody help with its (ii) part? It is from M/J 2012 v33 and the answer is 100/e.

 

[Unknown202]

can someone please solve this one a) and b)

 

[A*****]

can someone please solve this one a) and b)
View attachment 64408
View attachment 64409

Angle OCB=68° (Alternate angles)
Angle OBC=68° (Isosceles triangle)
BOC+68+68=180 ---> BOC=44°

BCE=180-68=112° (interior angles)
ACB=90° (angle in a semi circle)
ACE=360-112-90=158°

 

[Unknown202]

Angle OCB=68° (Alternate angles)
Angle OBC=68° (Isosceles triangle)
BOC+68+68=180 ---> BOC=44°

BCE=180-68=112° (interior angles)
ACB=90° (angle in a semi circle)
ACE=360-112-90=158°

so cuz the triangle is isoscles both angle are equal k thx alot

 

[Wâlèé Atèéq]

Can anyone help me? I'm in A2 and it's just 4 months left my subjects are Phy, Maths and C.S. Any hope ?

 

[A*****]

can some one please help me out ?

Post the complete question

 

[Ebrahim12]

View attachment 64411 View attachment 64412

(i)
It being a one mark question is a hint at a clever solution:

(ii)
From main diagram:
AreaTotal = 2*AreaB + AreaCircle (or 2*AreaSemiCircle)

AreaA = (i) - AreaB

 

[Ebrahim12]

Can anybody help with its (ii) part? It is from M/J 2012 v33 and the answer is 100/e.

View attachment 64388

Was your answer to the first part y = 70e^[e^(-3t) - 1] ?

As t goes to infinity,

e^-3t tends to zero​

thus,

y tends to 70e^[0 - 1] = 70e^-1​

so we have:

yFinal = 70e^-1
yStart = 70 (from main question)

p = (yFinal/yStart)*100
p = 100e^-1​