Mathematics: Post your doubts here!

[qwertypoiu]

HI. Can someone help me with this please?
QP: http://onlineexamhelp.com/wp-content/uploads/2013/11/9709_w12_qp_31.pdf
9709/31/ON/12 Q7 (ii). When I equate the denominator to 0, shouldn't I get both x=0 and 3y^3-1=0 ? Why does the mark scheme solve for only 3y^3-1=0?
MS: http://onlineexamhelp.com/wp-content/uploads/2013/11/9709_w12_ms_31.pdf
Thank you!

The equation was:
ln(xy) − y^3 = 1

Any logarthmmic function, ln(x), is only defined for the domain (0,infinity), this equation cannot be evaluated at x=0.

Domain is 0<x<inf.

btw I've been told that log functions are defined for negative numbers in more advanced mathematics, so this may be technically wrong but I think for A2 this is what you're supposed to know. (Cuz I never took A2)

 

[Farah Ismail]

Yea I know.. But will the equation of the tangent also be equal to 0? I saw some qs in which they did that

the equation of the tangent can be equated to zero if you move everything to a side, the gradient however will only be equal to zero if its at a stationary point, Can I see the question you're talking about?

 

[Farah Ismail]

Anymore doubts guys? Good luck everyone in all your exams

do you have the list of formulas used for S1??

 

[sara kamal]

When there are repeating letters in combinations, you split them into cases based on how many times the repeating letter occurs.
0A: 3C3 (choosing 3 from T,I,Z)
1As : 3 (from previous part)
2As : 3C1 (choosing 1 from T,I,Z)
3As: 1
Total = 8

thanku so much..

 

[sara kamal]

i m getting my answer of dy/dx=(sint-cost)/(sint+cost)
how to write it in terms of tan??
please explain..

 

[sara kamal]

http://freeexampapers.com/A-Level/Maths/CIE/2013-Nov/9709_w13_qp_32.pdf
in q8 part b,i drew the argand diagram but really dont get it how to find the least value of modulus z-w for points on these loci...
plzz explain anyone,would be really thankful!

 

[TheJDOG]

http://freeexampapers.com/A-Level/Maths/CIE/2013-Nov/9709_w13_qp_32.pdf
in q8 part b,i drew the argand diagram but really dont get it how to find the least value of modulus z-w for points on these loci...
plzz explain anyone,would be really thankful!

Check this link thanks to DaniyalK. Was my doubt too just use Pythagoras theroeom

 

[TheJDOG]

https://malaysia.answers.yahoo.com/question/index?qid=20140919190443AAmSFNU

Thank you

 

[TheJDOG]

do you have the list of formulas used for S1??

Hey no , I don't know statistics

 

[Aina]

http://onlineexamhelp.com/wp-content/uploads/2013/11/9709_s13_qp_32.pdf
help...q6 and q10 part ii

 

[Aina]

http://www.studentbounty.com/pastpa...athematics (9709)/2013 Jun/9709_s13_qp_31.pdf
plz tell me
Q7 part (b)
Q8 part (b)

 

[nadeem siddique]

Asslmaulaikum can anybody help me in 6 th question of 2012 October November paper 32

 

[Aina]

Here's 5 ii) , I'm 100% sure there's a much easier and faster way to do it, but sadly I don't know , so I did it in the long way. I still obtained the correct answers though, I'll sketch 8) i) for you soon .
If someone knows the easier way please do cooperate .
Thanks

 

[Kazi Sarmad Ali]

Statistics! Someone there?
Rescue me please.

 

[Ram97]

Statistics! Someone there?
Rescue me please.

Which topic??

 

[omaaaar]

http://maxpapers.com/wp-content/uploads/2012/11/9709_w14_qp_32.pdf
Last question vectors can someone explain and do it completely
And does anyone know how to understand vectors quickly I don't know shit about them and have an exam in 2 days

 

[Jennifer4678]

Hey can someone help me with this question please! Thanks

 

[Kazi Sarmad Ali]

Which topic??

Pemutations & combinations, Probability specifically.
Any Notes? Dey do bhaee!

 

[qwertypoiu]

i m getting my answer of dy/dx=(sint-cost)/(sint+cost)
how to write it in terms of tan??
please explain..

Divide every term by cost...
So:
(sint-cost)/(sint+cost) =(sint/cost-cost/cost) / (sint/cost+cost/cost) = (tant - 1) / (tant + 1)

 

[DaniyalK]

Hey can someone help me with this question please! Thanks

a ^2 = ln(4+8a^2)
e^(a^2) = 4 + 8a^2
e^(a^2) = (1+2a^2)/0.25
e^(-a^2) = 0.25/(1 + 2a^2) (taking reciprocal)
e^(-.5a^2) = 0.5/(1 + 2a^2)^0.5
0.5 = e^(-.5a^2) * sqrt(1+2a^2)