I'm an IGCSE Maths Teacher - Post your questions here.

[StudentXYZ]

ok, I understand now, thank you very much

 

[mak kings]

mj-2010-p21-Q17 c!!

 

[mak kings]

I'll write a as the angle of the sector. The formula for arc length is: a/360 * 2 * pi * radius.

The radius is 5r and the arc length is 4r so we have:

a/360 * 2 * pi * (5r) = 4r

Next make a/360 the subject of the equation:

a/360 = 4r / (2*pi*5r) --> a/360 = 4/(10*pi)


The question asks for the area of the sector. The formula is: a/360 * pi * radius^2

The radius is 5r again and we can use the a/360 formula that we found earlier. Substituting all this in gives:

Area = (4 / (10*pi) ) * pi * (5r)^2

If you simplify this (try this yourself) you get:

Area = 10r^2
S

If you're still stuck, please tell me exactly which parts you do understand and which parts you don't.

O U TAKE THE ARCLENGTH..AS ITS ANSWER IS GIVEN AND ..BY IT V CAN FIND THE VALUE OF a(angle of sector) IN TERMS OF r ..
:- if v use only the area of sector formula ..then v gt an answer in r plus a(angle of sector)...nd this a v dont want so v used that arc length 2 find the value!!!
SO HAV I UNDERSUD IT CORRECTLY!!!

 

[mak kings]

SIR CUD U PLZ EXPLAIN THE LINES OF SYMMETRY IN IT....I SAW markscheme...and it was 4...bt wen i do the symmetry as shown above .. iget 8.. plz tell :s

 

[Heba Iftikhar]

help plz!!
https://www.xtremepapers.com/community/threads/help-needed-for-igcse.25333/

 

[weirdoatlarge77]

HELP PLEASE.
Help with Question 19, part bi)
From paper: 0580/21/M/J/10

 

[mak kings]

sir cud u plz plz plz ..explain the following minor doubts !!!
OCT/NOV -2011-P22- Q1 .... i get 08 30 (time) .wen i subtract!
OCT/NOV-2011-P23- Q23(b) ......y dnt v take the time in mins wen dividing???
THNX IN ADVANCE ...!!!

 

[sundas]

Can you please tell me when to round off our answers to 3 significant figures and when not to? thanks for qp 2

 

[james1234]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s12_qp_23.pdf Q21 parts (a) and (b) ..

 

[hamza fakhr]

what types of calculators are allowed for math exam ???????

 

[notnek01]

O U TAKE THE ARCLENGTH..AS ITS ANSWER IS GIVEN AND ..BY IT V CAN FIND THE VALUE OF a(angle of sector) IN TERMS OF r ..
:- if v use only the area of sector formula ..then v gt an answer in r plus a(angle of sector)...nd this a v dont want so v used that arc length 2 find the value!!!
SO HAV I UNDERSUD IT CORRECTLY!!!

Sorry, I read your post twice but it's very hard to understand

Can you maybe try explaining again?

 

[notnek01]

View attachment 25062
SIR CUD U PLZ EXPLAIN THE LINES OF SYMMETRY IN IT....I SAW markscheme...and it was 4...bt wen i do the symmetry as shown above .. iget 8.. plz tell :s

Can you tell me which IGCSE paper/year this is from? I'm not sure which lines are part of the image or lines that you have drawn.

 

[notnek01]

help plz!!
https://www.xtremepapers.com/community/threads/help-needed-for-igcse.25333/

Are you seriously asking an IGCSE maths teacher (who you don't know) to help you cheat by discussing an exam that you haven't done yet?

Maybe I'm misunderstanding your thread. I really hope I am.

 

[notnek01]

HELP PLEASE.
Help with Question 19, part bi)
From paper: 0580/21/M/J/10

A position vector is a vector that starts from O.

E.g. r = 2: 4p + 2q

Start from O and move along 4p (move 8 units to the right) and then move along 2q (4 units up) then plot the point where you finish (coordinates: (8,4).

Can you do the rest?

 

[xpfaddict]

plz help me to solve this http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s11_qp_23.pdf question no 5

 

[notnek01]

sir cud u plz plz plz ..explain the following minor doubts !!!
OCT/NOV -2011-P22- Q1 .... i get 08 30 (time) .wen i subtract!
OCT/NOV-2011-P23- Q23(b) ......y dnt v take the time in mins wen dividing???
THNX IN ADVANCE ...!!!

1)

8hrs and 30 minutes is correct. Change this to minutes: 510 minutes.

So in this time, the bus leaves 510/15 = 34 times.

But remember that the last bus leaves at 1730 so you need to include one extra. So the answer is 34 + 1 = 35.

23b)

The answer needs to be in m/s so you can't use minutes. You need to convert minutes to seconds.

 

[notnek01]

Can you please tell me when to round off our answers to 3 significant figures and when not to? thanks for qp 2

If the answer has less digits than the full calculator display, write down all the digits you see (this kind of number is called 'exact').

If the answer is not 'exact', round to 3sf and for angles round to 1dp. Sometimes the question will ask you to round to something else so read the question carefully.

 

[notnek01]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s12_qp_23.pdf Q21 parts (a) and (b) ..

a)

First notice that the base is square so AC = DB.

Look at right-angled triangle ABC and use Pythagoras to find AC. And this is equal to DB.

Next MB = 1/2 DB.

Now look at the right-angled triangle MPB. You can use Pythagoras to find PB.


b)

Can you do this part now? You need to use trigonometry (sohcahtoa) methods to find the angle PBM.

 

[notnek01]

what types of calculators are allowed for math exam ???????

Any calculator in this list should be fine.

 

[notnek01]

plz help me to solve this http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s11_qp_23.pdf question no 5

You should be able to see that this is a quadratic graph so n=2. (it could also be n=4 or n=6 or any even n but this is not part of IGCSE).

Then remember that 'smiley face' quadratics have positive a and 'sad face' graphs have negative a. So this graph must have negative a.

So any negative integer value of a is OK e.g. a=-2.