Mathematics: Post your doubts here!

[Evangeline]

Need Help
View attachment 40896
Not able to solve the "d" part!

(1/2)^x=8 try to find a similar base to start with
Step 1:
8 is equal to 2^3 right? so that means that 1/2^x = 2^3 , to make the base similar x has to be a negative number so 2^-x = 2^3 so -x=3 and finally x= -3 hope you find this helpful , check it on your calculator too it will be equal to 8

 

[Evangeline]

how ?

5^y=k , 5^y+1 = (5)x(5^y) which is equal to 5k, hope this helps

 

[Evangeline]

can someone please help me solve part a , thanks

 

[MiniSacBall]

can someone please help me solve part a , thanks

Well i would be really able to help you if you could attach the qp, instead of capturing and then uploading just link to past paper and write the question you need help with. I would infact also refer to mark scheme, to help you get the answer according to your syllabus. I guess i can solve this question by using equations and by using graph ( dividing in the shapes) and then solving it. But i don't know which you should do with?

 

[Mahwish Khalid]

Hey guys, from your personal experience, which year's questions do you think will be repeated in this year's Maths IGCSE? And also, which topics do you think will come in the first paper i.e P2?

 

[Mohamed Mirza]

Hey guys, i really need help in 2 simple qs that i cant solve heres the link q20 and 21http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s08_qp_2.pdf paper 22
thanks and inshallah we all do very good in the upcoming olevels next week ameen ya rab al alameen

 

[DarkEclipse]

Hey guys, i really need help in 2 simple qs that i cant solve heres the link q20 and 21http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s08_qp_2.pdf paper 22
thanks and inshallah we all do very good in the upcoming olevels next week ameen ya rab al alameen

Q20 a) This is a question on sector areas, so remember the formula : Φ/360 * πr^2
Therefore, the area of AOD is 95/360 * π * 100^2 = 8290.31 square meters.
The area of BOC is 95/360* π *160^2 = 21233.20 square meters.
Now, the area of ABCD = area of BOC- area of AOD = 21233.2-8290.31= 12932.89 = 12900 square meters (rounded to the nearest 100).

b) Multiply the original, un-rounded number you got before, which is 12932.89 with 1.8.
Therefore, 12932.89*1.8= 23279.2 =23300 cubic meters (rounded to the nearest 100).

c) i) 1 cubic meter = 100 cm*100 cm*100 cm= 1 000 000 cubic centimeters.
1 cubic centimeter= 10 cm*10 cm*10 cm= 1000 cubic millimeters.
Therefore, 1 cubic meter = 1 000 000* 100= 1 000 000 000= 10^9 cubic millimeters.
Therefore, 23300*10^9= 2.33*10^13 cubic millimeters.

ii) Take the lower bound of 2 cubic millimeters, which is 1.5, and divide 2.33*10^13 with it.
2.33*10^13/1.5= 1.553*10^13

Q21 a) Calculate AC, which will be the base of △FAC.
AC^2= 600^2 + 800^2
or, AC= √1 000 000
= 1000 m
Now, Tan θ= 200/1000
or, θ= 11.3°

b) This is a question on bearing. First, find the angle of A from C, i.e. angle CAD in △CAD.
Tan θ= 800/600
or, θ= 53.13°
Now, to find the bearing, the angle must be either added or subtracted from 180°. To find out what you must do, you have to check to see that if you add the angle to 180° , what is your answer and whether it exceeds 360°. If it exceeds 360°, then you must not add it at all, but you must subtract it from 180°. However, since adding 53.13° to 180° gives 233.13°, and it does not exceed 360°, then this is correct.
Therefore, your answer should be 180°+53.13°= 233.13°= 233° (rounded to the nearest whole number).

 

[princess sofia]

can someone please help me solve part a , thanks

hope it helped

 

[Mohamed Mirza]

Please help
Variant 22 q17 b How do you find rotation by 90 degrees about a fixed point other than (0,0)
Hey man, i really need help in 2 simple qs that i cant solve heres the link q20 and 21http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s08_qp_2.pdf paper 22
thanks man and inshallah we all do very good in the upcoming olevels next week ameen ya rab al alameen

 

[Mohamed Mirza]

Q20 a) This is a question on sector areas, so remember the formula : Φ/360 * πr^2
Therefore, the area of AOD is 95/360 * π * 100^2 = 8290.31 square meters.
The area of BOC is 95/360* π *160^2 = 21233.20 square meters.
Now, the area of ABCD = area of BOC- area of AOD = 21233.2-8290.31= 12932.89 = 12900 square meters (rounded to the nearest 100).

b) Multiply the original, un-rounded number you got before, which is 12932.89 with 1.8.
Therefore, 12932.89*1.8= 23279.2 =23300 cubic meters (rounded to the nearest 100).

c) i) 1 cubic meter = 100 cm*100 cm*100 cm= 1 000 000 cubic centimeters.
1 cubic centimeter= 10 cm*10 cm*10 cm= 1000 cubic millimeters.
Therefore, 1 cubic meter = 1 000 000* 100= 1 000 000 000= 10^9 cubic millimeters.
Therefore, 23300*10^9= 2.33*10^13 cubic millimeters.

ii) Take the lower bound of 2 cubic millimeters, which is 1.5, and divide 2.33*10^13 with it.
2.33*10^13/1.5= 1.553*10^13

Q21 a) Calculate AC, which will be the base of △FAC.
AC^2= 600^2 + 800^2
or, AC= √1 000 000
= 1000 m
Now, Tan θ= 200/1000
or, θ= 11.3°

b) This is a question on bearing. First, find the angle of A from C, i.e. angle CAD in △CAD.
Tan θ= 800/600
or, θ= 53.13°
Now, to find the bearing, the angle must be either added or subtracted from 180°. To find out what you must do, you have to check to see that if you add the angle to 180° , what is your answer and whether it exceeds 360°. If it exceeds 360°, then you must not add it at all, but you must subtract it from 180°. However, since adding 53.13° to 180° gives 233.13°, and it does not exceed 360°, then this is correct.
Therefore, your answer should be 180°+53.13°= 233.13°= 233° (rounded to the nearest whole number).

thank you, you are awesome

 

[My Name]

can someone please help me solve part a , thanks

It will be area under the graph break the graph into trinagle trapezium and rectangles
find al those areas and add to get totl ditance

 

[Awesome12]

Help HELP NEED FAST
View attachment 40923
shoaib672002
Thought blocker
shazmina
fantastic girl
Karim Nabil
Awesome12

Ireland is given
So measure angle for northern ireland

(angle for northern ireland/360) * (x) = 2
Find x. which is the total population

Measure respective angles, divide them by 360 and then multiply the product by x

 

[Karim Nabil]

Help HELP NEED FAST
View attachment 40923
shoaib672002
Thought blocker
shazmina
fantastic girl
Karim Nabil
Awesome12

measure angles for each country and then compare values with northern ireland
e.g. if england measures at 270 degrees and ireland is 20
then cross multiply:
20-->2
270->x
x=(270*2)/20
x=27
then...repeat for remaining countries

 

[DarkEclipse]

Please help
Variant 22 q17 b How do you find rotation by 90 degrees about a fixed point other than (0,0)
Hey man, i really need help in 2 simple qs that i cant solve heres the link q20 and 21http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s08_qp_2.pdf paper 22
thanks man and inshallah we all do very good in the upcoming olevels next week ameen ya rab al alameen

All rotations follow the same matrix, that is
0 ------ -1
---------- for 90 degrees rotation
1 ------ 0

and

-1 ------ 0
--------------- for 180 degrees rotation.
0 ------ -1

 

[Mohamed Mirza]

All rotations follow the same matrix, that is
0 ------ -1
---------- for 90 degrees rotation
1 ------ 0

and

-1 ------ 0
--------------- for 180 degrees rotation.
0 ------ -1

u r awesome again, one last q
Why is the order of rotational symmetry 1 in Q1 A http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s10_qp_22.pdf
I KNOW THAT THE ORDER OF SYMMETRY OF THE STAR IS 5 AND 2 FOR EACH RECTANGLE BUT HOW IS THE ANSWER 1 MAYBE SUBTRACTION?? PLEASE NEED HELP IN THIS Q

 

[Mohamed Mirza]

All rotations follow the same matrix, that is
0 ------ -1
---------- for 90 degrees rotation
1 ------ 0

and

-1 ------ 0
--------------- for 180 degrees rotation.
0 ------ -1

I UNDERSTAND BUT HOW DO YOU FIND IT ABOUT A POINT (4,4), IS THEIR A FORMULA??

 

[DarkEclipse]

I UNDERSTAND BUT HOW DO YOU FIND IT ABOUT A POINT (4,4), IS THEIR A FORMULA??

No. It is the same for all points, regardless of position.

 

[DarkEclipse]

u r awesome again, one last q
Why is the order of rotational symmetry 1 in Q1 A http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s10_qp_22.pdf
I KNOW THAT THE ORDER OF SYMMETRY OF THE STAR IS 5 AND 2 FOR EACH RECTANGLE BUT HOW IS THE ANSWER 1 MAYBE SUBTRACTION?? PLEASE NEED HELP IN THIS Q

Because no matter how many degrees you rotate it , it is only symmetrical in one way.

 

[Evangeline]

View attachment 40913 hope it helped

Thanks Sofia

 

[DeadlYxDemon]

Just want to share with you all that yesterday I solved Maths paper 2 (variant 2) both june and November 2013 and honestly it was easy to do except for few questions like VECTORS, SEQUENCE, etc in which im not good at!