Mathematics: Post your doubts here!

[Haya Ahmed]

My doubt is just a confusion in the permutation combination how do we calculate for items not together .. what is the difference between using the way that
we make them together and subtract them from the arrangement of all (method 1).. or
multiplying by for eg we have 9 places and 4 items should not be together so 9P4 ?! (method 2)

.. why sometimes I get this wrong !!

for example here we use (method 2) in Q6 (iii)
http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s13_qp_62.pdf


and here we use (method 1) in Q7 (iii)
http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s13_qp_63.pdf


So can someone "Please" Explain what is the difference between this 2 methods and when to use each method .. thanks in Advance !!

 

[Thought blocker]

-Phew- !

 

[ZaqZainab]

My doubt is just a confusion in the permutation combination how do we calculate for items not together .. what is the difference between using the way that
we make them together and subtract them from the arrangement of all (method 1).. or
multiplying by for eg we have 9 places and 4 items should not be together so 9P4 ?! (method 2)

.. why sometimes I get this wrong !!

for example here we use (method 2) in Q6 (iii)
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s13_qp_62.pdf


and here we use (method 1) in Q7 (iii)
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s13_qp_63.pdf


So can someone "Please" Explain what is the difference between this 2 methods and when to use each method .. thanks in Advance !!

okay so method one which in my attachment is 3
is when Not all next to each other lets take an example
3 Blue pens and 4 green
Find the possible arrangements when not ALL green next to each other
we can have it like this
|||||||
but if its method 2 which is in my attachment 4
you cant have it like this you are suppose to have it
||||||| or any other way in which a green is not next to another green
BUT sometime both the methods work when you have
for example 3 blue and 2 green
just because the number is 2 that's why

 

[Haya Ahmed]

okay so method one which in my attachment is 3
is when Not all next to each other lets take an example
3 Blue pens and 4 green
Find the possible arrangements when not ALL green next to each other
we can have it like this
|||||||
but if its method 2 which is in my attachment 4
you cant have it like this you are suppose to have it
||||||| or any other way in which a green is not next to another green
BUT sometime both the methods work when you have
for example 3 blue and 2 green
just because the number is 2 that's why

LOAAAAAAAAAADS OF THANKS !!!!!!!!

 

[Ayeshak93]

This is a hard one....anyone? View attachment 42864

 

[daredevil]

This is a hard one....anyone? View attachment 42864

there;s an error on this file... try uploading it again

 

[Ayeshak93]

This is a hard one....anyone? Q.6 Part b...

 

[Ayeshak93]

I think I uploaded it again, check?

 

[zoza7elw]

View attachment 42867 View attachment 42867 View attachment 42867 I think I uploaded it again, check?

There is nothing hard in Part (ii) just put the number 1 instead of theta and then on your calculator replace that (1) with (Ans) and find following answers till it converges to value of theta
That's all

 

[Ayeshak93]

There is nothing hard in Part (ii) just put the number 1 instead of theta and then on your calculator replace that (1) with (Ans) and find following answers till it converges to value of theta
That's all

Oh sorry I meant part a...

 

[zoza7elw]

Oh sorry I meant part a...

Ok, Ya that's part was hard

 

[zoza7elw]

Oh sorry I meant part a...

Ok, Ya that's part was hard

 

[leadingguy]

thats nopt the answer

That was the exact answer. plz Check mark scheme
both steps and answer are correct. scoring 4 marks.

 

[Rutzaba]

That was the exact answer. plz Check mark scheme
both steps and answer are correct. scoring 4 marks.

21. sumthing

 

[leadingguy]

yes!! (- 41.4 + 52.24 )*2 = 21. something.

now if you did not put the - sign with the 41.4 then even that step marks will be allotted and
if you insist that where does that minus comes from than it is upto us. As these are some trigonometry rules we learnt in add maths.
Rutzaba

 

[Rutzaba]

yes!! (- 41.4 + 52.24 )*2 = 21. something.

now if you did not put the - sign with the 41.4 then even that step marks will be allotted and
if you insist that where does that minus comes from than it is upto us. As these are some trigonometry rules we learnt in add maths.
Rutzaba

cos haina to minus theta kiu lia hum ne/

 

[Rutzaba]

yes!! (- 41.4 + 52.24 )*2 = 21. something.

now if you did not put the - sign with the 41.4 then even that step marks will be allotted and
if you insist that where does that minus comes from than it is upto us. As these are some trigonometry rules we learnt in add maths.
Rutzaba

A*(a*)

 

[Rutzaba]

yes!! (- 41.4 + 52.24 )*2 = 21. something.

now if you did not put the - sign with the 41.4 then even that step marks will be allotted and
if you insist that where does that minus comes from than it is upto us. As these are some trigonometry rules we learnt in add maths.
Rutzaba

thanks yar

 

[xXGTZXx]

anyone mind explaining foot of the perpendicular to me in vectors

eg
http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_s04_qp_3.pdf
Q11

thx

 

[salvatore]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s13_qp_31.pdf
Pleaseee help me with qn no. 6(ii), I'll be grateful!
Thanks