# Toffu-san

Members

31

1 Unknown

• Gender
Male
• Exams
May 2010
• Country
Spain
1. ## Any specific REAL math problems you need help with?

I can't see the first because I'm not VIP, but for the second one you say that you have the value of sqrt (3) and the value of tan(15), you can see that sqrt(3)+tan(15)=2, consequently 2^5=32. a=32 b: (cos(116)·cos(244) + cos(23)·sin(67) + cos(67)·sin(23) - sin(116)·sin(244))=(cos (116+244)+sin (67+23)) (remember that sin (a+b)=sin (a)·cos(b)+sin(b)·cos (a) and cos (a+b)=cos(a)·cos(b)-sin(a)·sin(b) ) (cos (116+244)+sin (67+23))=(cos (360)+sin (90))=1 b=4·1=4 Now you have this: log324=2/5
2. ## Maths Textbooks

I recommend you the Haese & Harris HL Book (http://www.ibbookshop.co.uk/catalog/product_info.php?manufacturers_id=23&products_id=363&osCsid=710ed9d60daebc6dec20fec390cb1c75) I used it and it's good.
3. ## When is a math protfolio a good one?

I have done a portfolio Type 1 and it has 27 pages. I write a lot of evident things but.... I think that at least 10 pages.
4. ## Matrix Pattern?

If look carefully the first five "n" you have this: A: [2 1] [1 0] A^2: [5 2] [2 1] A^3: [12 5] [5 2] A^4: [29 12] [12 5] A^5: [70 29] [29 12] If we rename the matrix we will see it better: A^n: [a_n b_n] [c_n d_n] First we have that: b_n=c_n Then: a_1:2 b_1:1 d_1:0 We can see that: i_n=2*i_{n-1}+i_{n-2} We can only apply this rule since n=3. I wish to have helped you EDITED: Now you have to solve the recursion and to prove by induction that it's true.
5. ## IB Math SL Portfolio Format?

I think that there is not an specific method of presentation for the protfolios because IB is everywhere and there are a lot of different presentation methods.
6. ## Any specific REAL math problems you need help with?

First of all you have that the point P is equidistant from A and B. If we call "d" the distance between two objects we have that: d(A,P)=d(A,B) These distances are the magnitude of the vectors AP and BP. Now we have that: If we operate it, you finally have: This is the locus of all the possible P points. It's is a line, we can rewrite like: x+y-3=0 We know that P lies on y=2·x-9. Now we only have to found the intersection: 3x-12=0 x=4 4+y-3=0 y=-1 Ergo, P=(4,-1).
7. ## Math problems

I will try to answer you: The first one: You have to know the expansion of (x+y)^n (Newton's Binome, http://en.wikipedia.org/wiki/Binomial_theorem), then we have that: We have that k=3, for this motive the coefficient of the term x^3 is: 2^(10-3)· a^3 · 10!/(3!·7!)=414720 Now you can find a . For second one: We know that in a quadratic equation the solve for a·x^2+b·x+c=0 is x=(-b+-sqrt{b^2-4ac})/2a, if this equation have to have two distinc real roots, must exist sqrt{b^2-4ac} in R and it have to be different to 0 (if it was zero it will have a double root). For this motive b^2-4ac>0. Then: (-2·k)^2-4>0 4·k^2-4>0 k^2>1 |k|>1 I hope to have helped you.
8. ## 7 Subjects...?

I'm doing 7 subjects too: Maths HL (probably Further Maths SL), Biology HL, Physics HL, Chemistry SL, English B SL, Catalan HL, Philosophy SL (but I'm coursing it at HL). But I'll only examine of 6 (all except Biology), althought I'm thinking to examine of Biology SL. If I were you, I will try to do all the subjects you can and at the moment to decide about what subjects you will examine choose the ones you like more. But, prepare yourself! Good luck!
9. ## Spanish Ab Initio students: ¿Dónde estáis?

Sería por qué no creamos. Creeremos es el futuro simple del verbo creer (to believe). Estoy de acuerdo contigo, crea el tema y adelante. Propón un tema de conversación polémico (aborto, eutanasia, etc) y todos los que quieran aprender podrán practicar.
10. ## Chemistry Study Guide vs. Chemistry Course Companion

I have the study guide for chemistry and I think that it's better than the course companion. In the course companion there is a lot of innecessary text, and if you understand the subject you only need the study guide. But I'm doing Chemistry SL, and I don't know if HL is so further than the SL.
11. ## Further Mathematics Book

We (GNRS and me) will finally get the Haese Harris HL book and the Haese Harris HL Options book. Our teacher recommended it to us. Thanks for all
12. ## Further Mathematics Book

There are four difficults in IB Maths: Maths Studies, SL, HL and Further Mathematics SL. It's called SL but is harder than the others levels. There is no Further Mathematics HL, it's only his name; and is the best level preuniversty of maths.
13. ## IBID Maths HL CD

You can download the CD from this link: *** It's a torrent, the original file have 80 MB and it's too big to upload.
14. ## Further Mathematics Book

I'm probably going to course Further Mathematics SL and my teacher asked me to search a book wich have all the topics of the syllabus. Is there anyone that have done it? What book did you use? How difficult is it? Thanks
15. ## Contributing=VIP status?

I don't understand what kind of notes I have to upload, to contribute. Can you explain it? Thanks!
×