Mathematics: Post your doubts here!

[princess Lulu]

help me in statistics please :s am really stuck.. ;s

 

[Moar]

Hi guys
i have a very technical question.
what is an exact value ?

like in the question no.1 , wat should be the answer ?
is it 4.50 x 10^9 or 4.496 x 10^9
i checked the marking scheme , it says its 4.496 x 10^9 but shuldnt we round this off to 3s.f ???

dude you don't round in standard form the answer is totally different then .

 

[Razo513]

help me in statistics please :s am really stuck.. ;s

post the question

 

[Razo513]

http://www.xtremepapers.com/papers/CIE/Cambridge IGCSE/Mathematics (0580)/0580_w08_qp_04.pdf
Question 10.Thanks

hope it helped , if u want to explain anything just tell me

 

[999]

Thank you so much!
I understood everything except c(ii).
Could you also help me in winter 09 paper 4 question 10 f and g, summer 2010 paper 4 question 11 part d.
Sorry i didnt ask you in the other post. nth term is the only thing I have a problem in. Im good at everything else.

 

[Razo513]

Thank you so much!
I understood everything except c(ii).
Could you also help me in winter 09 paper 4 question 10 f and g, summer 2010 paper 4 question 11 part d.
Sorry i didnt ask you in the other post. nth term is the only thing I have a problem in. Im good at everything else.

haha it's ok ... ill see the questions now ... abt c (ii) look at the numbers all are odd ... in the first formula given look at the numbers both even & odd... in the second formula we have the even formula so now how do we get the odd formula from those 2 given formulas simple the formula of all the numbers together - the formula of the even numbers = formula of the odd number ?? so u got it give me sometime & ill help u in the others

 

[999]

Thanks .
Really helped. Take your time on the others.

 

[Razo513]

Thank you so much!
I understood everything except c(ii).
Could you also help me in winter 09 paper 4 question 10 f and g, summer 2010 paper 4 question 11 part d.
Sorry i didnt ask you in the other post. nth term is the only thing I have a problem in. Im good at everything else.

ok now for w09 10 f) it's rlly simple not as hard as u think they gave u a big hint they told u that the total of the first even numbers is n(n+1) & they asked u what will the formula be if u have (n-1) same thing n(n-1) is the answer
for g) i wasnt rlly able to get this but m guessing is that (n^2-n+1)+ n(n-1) =n^3 i didnt get the one for letter e much ??
srry
well i have a very awkward method to solve s10 11d) (i) i think & 100% unsure abt this that k(n^2+n+1)=2n+3+n^2 solve for k u will get 1.6 i guess to get k u can round to 2 but as i said ask other's maybe u will get better replies...based on k in (i) u can then get (ii) ......im rlly sorry abt this but some questions arent friendly with me i guess hope i helped if even a bit

 

[999]

Dont worry you helped me alot.
I understand nth term questions more than i did before so thank you!

 

[shaheer salim]

sure thx

umm m reeeli sorry for replyn late had dome technical issues

there u go temi if u understood xD

 

[Razo513]

umm m reeeli sorry for replyn late had dome technical issues

there u go temi if u understood xD

WOW never thought ill get that easily thx .... just one more question which is better using the In or Log method cuz i never rlly used either of them when solving i depended on my guessing

 

[Moar]

uhh hey shouldn't you show the working not just what you used in the calculator, i mean as in keep dividing it by prime numbers till you reach 2
I am doing edexcel math here but i think in both cases u will need to show working , so does the log thing counts as working?

 

[Razo513]

uhh hey shouldn't you show the working not just what you used in the calculator, i mean as in keep dividing it by prime numbers till you reach 2
I am doing edexcel math here but i think in both cases u will need to show working , so does the log thing counts as working?

well , in such questions 1 mark is only given most of the time in igcse idk about edexcel.. but i took dividing by prime numbers method in school.. never rlly suited me , but if i have to ill use this log method for correction to make sure of my answer =P but stick to the one in school i guess

 

[shaheer salim]

WOW never thought ill get that easily thx .... just one more question which is better using the In or Log method cuz i never rlly used either of them when solving i depended on my guessing

lol ur most welcome.. n well i don reeeli knowh the In method lol but hmm i think logs better xD

 

[Zeerik]

I have Dont Know When to Use the Sine Rule and How to Calulate the Angles!?? Im Having the May/June Session

 

[Moar]

I have Dont Know When to Use the Sine Rule and How to Calulate the Angles!?? Im Having the May/June Session

You use the sine rule when you have two sides and angle that is not in between , or if you have two angles and a side .
The rule is simply sinx/opposite side = siny/opposite side
so you are basically dividing the sin of angle over its opposite side
THE ANGLE should not between two sides, or else it is cosine rule.
Good luck , and i wanted to put an example but i am on a rush i hope this was helpful though

 

[Busy Buddy]

Assalamualaikum...
Can you please provide some simple key points to remember on sets & probability because I'm facing problems in those chapters!

 

[sma786]

http://www.xtremepapers.com/CIE/Cambridge IGCSE/0580 - Mathematics/0580_s09_qp_2.pdf (paper 21)

i have a doubt in question number 22 .. isnt is supposed to be that we have to find the LCM of the two fructions with the substracting sign? the final answer m getting is 1/cd .. but it is 2/c .. help pleasE !

 

[Iridescent]

http://www.xtremepapers.com/CIE/Cambridge IGCSE/0580 - Mathematics/0580_s09_qp_2.pdf (paper 21)

i have a doubt in question number 22 .. isnt is supposed to be that we have to find the LCM of the two fructions with the substracting sign? the final answer m getting is 1/cd .. but it is 2/c .. help pleasE !

question 22 is an angles question, i guess u mentioned the wrong number.

 

[Moar]

Assalamualaikum...
Hey XPF member, can plz provide sum simple dpoints to remember on sets n probability coz I mostly face problems in these chapters!

You need to know in sets the venn diagram very well so you know that point of intersection is for example x, and that each complete circle is x+number giving on it.
For example if you have 12 students playing football only and two plays both football and hockey , and those playing hockey are 14. First of all obviously the universal is 12+14+2= 28
Now for example if you didn't have the amount of ALL students playing hockey but u had all other giving (the universal '28' , the number of students playing football, and the number of students playing both hockey and footbal '2') and where asked to find the amount of students playing hockey (including those playing football too).
Then let x= the number of student playing hockey therefore: 12 + 2 + x-2 = 28
so 14+x-2=28
x-2= 28-14
x=14+2
x=16
and if students play hockey only is required then 16-2= 14
Now you need to know that when they ask for n(P) for example you will write a value not members , if the asnwer is invalid then you put 0. If members are asked you write all the possible members in this set, and if not possible you put

(null sign).
Also you need to understand these symbols: ∩ (intersection) ,
∪ (union)
⊆ (subset as in it is a small set in a larger one)

Now for the probabilty just quick tips
1- and is multiply
2-or is add
3- if it says without replacement means that you reduce the total by 1 , and this element total by 1 (i.e : if there are 15 apple , 4 are green , if he takes an apple and doesn't replace it , then probability now is 3/14)
4- Use tree diagram if you are stuck
5- if it says estimate the number of times this probability will occur in 3o spins for example if referring to a spinner having numbers from 1 to 5. If probability of it landing on 1 is o.5 , then you multiply 0.5* 30= 15 times
6- If you have too many probabilities for your answer then subtract all the unwanted probabilities from 1 to give you the answer of the wanted probability.

That is pretty much everything i can remember for now , btw i am doing edexcel not Cambridge math so i am not sure how much can this be useful for you but we are not that different in sets and probability , anyway hope i helped even a little. If you need any assistance i am ready to help you