Mathematics: Post your doubts here!

[notnek01]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s08_qp_2.pdf
question 16
guys..i got the answer right (using calculator) but i dont know the working
care to show me?

This is a standard simultaneous equations question that you need to know how to do.

Multiply the first equation by 3 and the second equation by 2 to give:

6x + 9y = 33
6x - 10y = -24

Now subtract the equations. Can you finish it from here?

 

[xpfaddict]

10(1-x/10) – (10-x) – 1/100 (10-x) =0.05

plx sove this

 

[ZaqZainab]

10(1-x/10) – (10-x) – 1/100 (10-x) =0.05

plx sove this

Yo I started solving it but i just wanted to make sure your question is 10(1-x/10) – (10-x) – 1/100 (10-x) =0.05
Or 10((1-x)10)-(10-x)-(1/100)(1o-x) =0.05
Well this is kinda confusing can i have look at the original question cause we can't write it clearly over here!

 

[uzair shahid]

guys for shear and stretch! don't learn the way because its complex learn it in the matrix form! and multiply their matrix by the points the lay in that shape!

can u please tell me all the matrix forms?

 

[notnek01]

can u please tell me all the matrix forms?

Here they are.

 

[tweetie]

15b) use the ratios rule, square the ratio 1:5 and you will get 1:25 and 12:x, solve for x ie 300

21c) draw a tree diagram with three branches(RBG) and you will find 3 probabilities: RG(3/9*2/8),BG(2/9*4/8) and G and NOT G(ie blue+red(4/9*3+2/8)
that should give you 5/9

sorry but i didnot understand any of thm / :/

 

[Princess Raven]

guys!!! for sets how in the world are we suppose to know when we have to shade everything or only the circles? for ex A' U B do we shade the box or only B??? HELP PLX

 

[notnek01]

guys!!! for sets how in the world are we suppose to know when we have to shade everything or only the circles? for ex A' U B do we shade the box or only B??? HELP PLX

Rules for shading:

A U B : First shade all of A and then shade all of B. Some parts may be shaded twice but that doesn't matter.

A ∩ B : First shade all of A and then shade all of B. Then erase anything that hasn't been shaded twice.


So for A' U B, you first shade everything that is not in A (this includes the outside box area). Then shade all of B.

 

[AmazynGal]

how to solve question 10 and 20 paper 2 oct/nov 2007

 

[tweetie]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w11_qp_41.pdf
q4b(i) y will we minus 2.7 from 4.5.....while the radius of the cup is 4.5...so why shld we sbtract
q6b- y the answer is not 48.5?? y is it 131?
PLEASE HELP ASAP......

 

[Princess Raven]

Rules for shading:

A U B : First shade all of A and then shade all of B. Some parts may be shaded twice but that doesn't matter.

A ∩ B : First shade all of A and then shade all of B. Then erase anything that hasn't been shaded twice.


So for A' U B, you first shade everything that is not in A (this includes the outside box area). Then shade all of B.

ahhhh smart!!! ty a lot.. so one more question as u said for A' U B we shade the box too.. so how about A' ∩ B do u also shade the outside box?

 

[Princess Raven]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w11_qp_41.pdf
q4b(i) y will we minus 2.7 from 4.5.....while the radius of the cup is 4.5...so why shld we sbtract
q6b- y the answer is not 48.5?? y is it 131?
PLEASE HELP ASAP......

ok i didn't get what u said.. the answer is 8.2 as given so u should find the slant height of the whole cone then of the small come using Pythagoras theorem and just subtract to get the slant height S

 

[Princess Raven]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w11_qp_41.pdf
q4b(i) y will we minus 2.7 from 4.5.....while the radius of the cup is 4.5...so why shld we sbtract
q6b- y the answer is not 48.5?? y is it 131?
PLEASE HELP ASAP......

ok and q6 is a really good question.. but read it very carefully.. it says OBTUSE angle and when we get 48.5 thats acute so minus it from 180 to get the obtuse part.. usually in math when a word is written in bold.. u should stress on that part.. many make this mistake

 

[tiki-taka]

0580/43/o/n/11
Q5-(b)

HELP!!

 

[uzair shahid]

Here they are.

shear x axis invariant i think u made a mistake..

 

[notnek01]

shear x axis invariant i think u made a mistake..

Yes I did - thanks for noticing

I'm sorry to anyone who used my list! Here's the corrected version.

 

[Princess Raven]

ppl... http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w12_qp_41.pdf
q 9 part c? y dont we divide since its in second so to make it into 365 Days we do... 300000/3600/24/365 but the ms shows 300000x3600x24x365??

 

[Batrisyia]

First of all,the answer to this:[ AA^-1 & A^-1 A ] Which one is the correct way to use and will the answer BE DIFF?

Here. Find P if Q=[2 -1 (4&0 below) ] and PQ= [ 6 -3 (8 & -2 below) ]



PS: I have another one tho. :/ Anyone here good at this?

 

[notnek01]

how to solve question 10 and 20 paper 2 oct/nov 2007

10)

First find the area of the big semicircle. This is:

pi*r^2 / 2 = pi*(12^2)/2 = ...

Then find the area of the small semicircle:

pi*r^2 / 2 = pi*(6^2)/2 = ...

And finally subtract these two answers.


20)

There are many isosceles triangles here: AOD, AOB, OBC and OCD. Can you fill in all the angles?

E.g. In AOB, the two unknown angles must be 45 and 45.

 

[notnek01]

ahhhh smart!!! ty a lot.. so one more question as u said for A' U B we shade the box too.. so how about A' ∩ B do u also shade the outside box?

A' ∩ B : First shade A'. This is everything not in A (including the part outside the circles).

Then shade all of B.

The part that has been shaded twice is the answer (erase everything else).

Here's a diagram to shows this:

The \ lines show A' and the / lines show B. Then the shaded area is the part that has been shaded twice.



If you call A', "not A" and ∩ "and", then it makes things easier. E.g. A' ∩ B is "B and not A". So this is everything in B that is not in A.