Help pls, H2 A lvl Integration Application

• limywv

  20 Dec 08, 11:58

  
  

   

   

  
  
• eagle

  20 Dec 08, 12:43

  (ii)

  Point A = (π/3, √3)

  Rotate around x-axis (which is y=0 line)

  So,volume = volume of cylinder - volume rotated under curve OA around x-axis

  

  

  

  

  

  I might be careless as I did everything offhand online mentally... Do check :D

   

   

   

• eagle

  20 Dec 08, 12:49

  (iii) I assume you are integrating w.r.t y, since you didn't state it

  

  Substitute y = tan x

  Integral becomes

  

  but

  

  So integral becomes

  

  

  = 1.5

   

  Again, do check... Feeling a bit sleepy.

   

• eagle

  20 Dec 08, 12:50

  Btw, do contribute part (i)

  I would like to add this question to ExamWorld as well :D

• limywv

  21 Dec 08, 00:36

  
  

   

   

  
  
• wee_ws

  21 Dec 08, 07:13

  Hi Eagle,

    The question is a past-year question from Nov 2002.

    We should join forces to teach H2 maths leh. Btw, I left a Physics TYS Solns Book for you at the centre with Rick.

    Merry christmas!

  Cheers,
  Wen Shih

• wee_ws

  21 Dec 08, 07:18

  Hi,

    Part (iii) has a shorter approach to solving it, which is to take the difference between the area of rectangle and area of region R.

    Thanks!

  Cheers,
  Wen Shih

• eagle

  21 Dec 08, 08:06

  Originally posted by wee_ws:

  Hi,

    Part (iii) has a shorter approach to solving it, which is to take the difference between the area of rectangle and area of region R.

    Thanks!

  Cheers,
  Wen Shih

  I was thinking of that, but I could not confirm as I was too tired when doing it that day although it was noon :D

• eagle

  21 Dec 08, 08:06

  Originally posted by wee_ws:

  Hi Eagle,

    The question is a past-year question from Nov 2002.

    We should join forces to teach H2 maths leh. Btw, I left a Physics TYS Solns Book for you at the centre with Rick.

    Merry christmas!

  Cheers,
  Wen Shih

  I need to brush up on statistics and graphics calculators, that's why :(

• UltimaOnline

  21 Dec 08, 11:54

  Originally posted by wee_ws:

  Hi Eagle,

    We should join forces to teach H2 maths leh.

  Cheers,
  Wen Shih

  -----------------

  Hi Eagle,

    We should join forces to teach H2 maths leh.

  Cheers,
  Wen Shih

  -----------------

  
  If Wen Shih and Eagle were to jointly teach, they could deal with a much larger class at once, eg. 20+ students. That would mean significantly more income (even after splitting 50-50) for each/both of them.

   

  This may appear mathematically invalid (times 2 divide by 2 = same?), but it's really about synergy and mutually beneficially arrangements, of which there could be several different ways to work with and benefit from "joining forces).

   

  For instance, each teacher tutor could arrange to handle different topics of any the H2 mathematics syllabus. Then, the class of say, 20 students, would have some students going to Wen Shih, some students going to Eagle, and some students doing their school assignments.

   

  Of course, scheduling will be tricky, as both men are obviously busy people. But if it could work, it may well be worth it.

   

  

• limywv

  22 Dec 08, 18:53

  
  

   

   

  
  
• 16/f/lonely

  22 Dec 08, 21:46

  The stuff you guys can do online never fails to amaze and boggle me.

• wee_ws

  22 Dec 08, 22:07

  Dear limywv,

    Draw a diagram and see for yourself what I said about the difference between the rectangle and area of region R. Thanks!

  Cheers,
  Wen Shih

• limywv

  22 Dec 08, 22:29

  
  

   

   

  
  
• eagle

  22 Dec 08, 23:12

  my part (iii) is wrong... substitution is wrong if you realised...

  I have yet to find the time to edit it on examworld :(