Mathematics: Post your doubts here!

[Hamzeh S]

haha i got everything except why 12+36 not 36-12?

 

[aliiiiiiiiii]

finding the mid speed ?? add the values then devide them by the number of values added which is 2!! ull get da same ans but u will not devide again later

 

[Hamzeh S]

ohh thanks so i should always find average speed when finding area under time speed graph?

 

[Hamzeh S]

of a triangle ?

 

[afshinsalim]

Assalam u Alaikum

It is mentioned that line AB is 100meters.
First, you have to measure the length of line AB using a rule, let's say x cm.

You have to simplify them into their lowest form, but the unites aren't same. Either convert the cm in meter by dividing by 100 or convert the meters into cm by multiplying by 100. I personally prefer the latter. Now you have x:10000.

Simplify till you get x as 1 and then you have n.

Hope it helped.
I am appearing for May/June 2012 for six subjects and I didn't prepare for any but Physics. Please pray.

Ill pray 4 u dont worry. BTW m sooo bad at physics. I hate that subject. Im taking 8 subjects n m writing in may/june 2. Pray 4 me 2. N ur answer helped alot thnx

 

[afshinsalim]

Use a scale to measure the length of AB in the diagram
then:

Actual : Map
10000 cm : (whatever is the length of AB in the diagram)

Simplify to get the value of n!

Thnx

 

[kboss]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w10_qp_41.pdf
i.e 0580 o/n 2010 qp 41
can u explain how to do the last question?
thanks in advance ;D

 

[Nidal]

May june 2011 qp42 question 9) c) anyone explain please ?

 

[topgun]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w10_qp_41.pdf
i.e 0580 o/n 2010 qp 41
can u explain how to do the last question?

thanks in advance ;D

Assalam u Alaikum.
Sure!

9)
ai) P6 = 1+2+3+4+5+6 = 21.
aii) Substitute 6 in the place of n. This gives 1/2 (6) * [(6)+1]. This would give the answer, 21, which is the same as our previous answer, hence the formula works!
aiii) We do the same thing like aii. 1/2 (50) * [(50)+1]. This would give an answer of 1275.
aiv) Because the last value is 150, this gives a value of P150 . 150 is thrice the size of 50, so we multiply our answer in part aiii by 3. The answer is 3825.
av) This question is similar, except for the fact that we use the formula instead. 1/2 (150) * [(150)+1] = 11325.
avi) Apparently the answer is av-aiv. I don't understand how to do it myself, so sorry. The answer is 7500.

b)

The part b is a little tricky. If you look at whole thing, line by line, you will notice a change. The first line has 1x1 because there is just one '1'. The second line has 1x2 because there are two '1'. That is the pattern, the first number is the next number in series whereas the second number shows how many times has the first number been posted.

Going through this, the answer for part bi) is.

(1x6)+(2x5)+(3x4)+(4x3)+(5x2)+(6x1) = 56.

bii) 1/6 (6) [(6)+1][(6)+2] = 56.

c) 56-35 = 21. Our ai) is also 21.
d) You can substitute any value in the place of n, from 1-5 (we already took six) and check. It's going to be a bit lengthy so I am leaving the working.

Hope it helps. Pray for my M/J 12 IGs

 

[Hamzeh S]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s11_qp_42.pdf

question 3 part i know it so silly but when i measure it it gives me 6.8 :S whyy? with a rule i knw it is so stupid but excuse me i wanna know my mistake thanks a lot

 

[GetSomeLife]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Mathematics (0580)/0580_s11_qp_42.pdf

question 3 part i know it so silly but when i measure it it gives me 6.8 :S whyy? with a rule i knw it is so stupid but excuse me i wanna know my mistake thanks a lot

6.8? It must be more... something above 7 cm.

Then you multiply it with the scale and of the diagram which in this case is 1 : 20 and you'll get the actual distance

 

[Hamzeh S]

6.8? It must be more... something above 7 cm.

Then you multiply it with the scale and of the diagram which in this case is 1 : 20 and you'll get the actual distance

hahah i knw i need to multiply it but when i measure its its 6.8 :S idk yy hahaha its freaky

 

[kboss]

Assalam u Alaikum.
Sure!

9)
ai) P6 = 1+2+3+4+5+6 = 21.
aii) Substitute 6 in the place of n. This gives 1/2 (6) * [(6)+1]. This would give the answer, 21, which is the same as our previous answer, hence the formula works!
aiii) We do the same thing like aii. 1/2 (50) * [(50)+1]. This would give an answer of 1275.
aiv) Because the last value is 150, this gives a value of P150 . 150 is thrice the size of 50, so we multiply our answer in part aiii by 3. The answer is 3825.
av) This question is similar, except for the fact that we use the formula instead. 1/2 (150) * [(150)+1] = 11325.
avi) Apparently the answer is av-aiv. I don't understand how to do it myself, so sorry. The answer is 7500.

b)

The part b is a little tricky. If you look at whole thing, line by line, you will notice a change. The first line has 1x1 because there is just one '1'. The second line has 1x2 because there are two '1'. That is the pattern, the first number is the next number in series whereas the second number shows how many times has the first number been posted.

Going through this, the answer for part bi) is.

(1x6)+(2x5)+(3x4)+(4x3)+(5x2)+(6x1) = 56.

bii) 1/6 (6) [(6)+1][(6)+2] = 56.

c) 56-35 = 21. Our ai) is also 21.
d) You can substitute any value in the place of n, from 1-5 (we already took six) and check. It's going to be a bit lengthy so I am leaving the working.

Hope it helps. Pray for my M/J 12 IGs

thanks again
bt i forgot to mention that i was actually referring to d) only...
so it would be appreciated if u could solely explain that in detail.
sry for the prior mistake.

 

[slayer]

Please guys need help with Q 19 http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w04_qp_2.pdf

 

[Rahatkhanrk]

WHO IS APPEARING FOR 2012 MAY/JUNE EXAMS ???

 

[GetSomeLife]

Please guys need help with Q 19 http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w04_qp_2.pdf

It's easy:

They said the TOTAL length of the border is 400 m
The radius of the two semicircles is given as 35 m
Let the total length of the straight parts be x

(a) (2 * pie * 35)/2 + (2 * pie * 35)/2 + x = 400
219.901 + x = 400
x = 400 - 219.901
x = 180 m

(b) The straight distances are the same for both the inner and the outer lane, so we can ignore them!

Total length of the inner semicircles = (2 * pie * 35)/2 + (2 * pie * 35)/2 = 219.901
Total length of the outer semicircles = (2 * pie * 41)/2 + (2 * pie * 41)/2 = 257.612
I wrote 41 as there are 6 lanes and EACH lane increases it's length by 1 m!

Difference = 257.612 - 219.901 = 37.7 m

 

[topgun]

thanks again
bt i forgot to mention that i was actually referring to d) only...
so it would be appreciated if u could solely explain that in detail.
sry for the prior mistake.

No problems.
The given formula is:
[Pn = 1/2n(n + 1)]
Let us take n as, say 4. This would change the formula to [P4 = 1/2 (4) ((4)+1)] The answer of this is 10.
Now the first formula says, Sn-Sn-1=Pn. We already got Pn, which is 10. Now substitute the value 4 in the places of n in the formula in bii). This gives the value of sn = 20. Now the value of Sn-1 will be found by substituting n-1 that is 3, in the place of n in the same formula. This gives an answer of 10. So, Sn-Sn-1 = Pn. Using the figures we got, 20-10 = 10. The value of Pn we found in the beginning was 10 too so our working is right.

Please guys need help with Q 19 http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w04_qp_2.pdf

19 a) The two semicircles have radius of 35m. That means, two semi circles with 35m radius each forms one complete circle (the area and perimeter). So, using the formula, 2xpiexr, we get 2xpiex35 = 70xpie
The question says that total distance of the track is 400m, so we minus our answer. So 400-70pie is 180m.

19b) It says that each lane is one meter wider. That increases the radius by 1 meter, whereas the length of the parallel track remains same. We are asked to find the distance between the length of the inner line of first track and outer line of last track. This is the sixth track so radius increased by 6m, to 41m. So, 41-35 gives us 6. We substitute 6 in the formula to find circumference, 2xpiex6. This gives value of 12pie or 36.699 which we can round off to 37.7m.

 

[stubborn angel]

hello can any1 plz write these numbers in standard form.....
(a) 734 000 000
(b)0.000587
(c)0.0004
(d)5,508
itz urgent plz my paper is on cmng tuesday.....

 

[étudiante]

hello can any1 plz write these numbers in standard form.....
(a) 734 000 000
(b)0.000587
(c)0.0004
(d)5,508
itz urgent plz my paper is on cmng tuesday.....

7.34 x 10^8
5.87 x 10^-4
4 x 10^-4
5.508 x 10^3

btw... if u have issues wid dis, u can do it directly on ur calculator

 

[stubborn angel]

7.34 x 10^8
5.87 x 10^-4
4 x 10^-4
5.508 x 10^3

btw... if u have issues wid dis, u can do it directly on ur calculator

ohh thanksshh aloot....