differential eqn.. help!

• hisoka

  15 Jan 07, 09:47

  Originally posted by missallsunday:

  haha i am a he . Anyway any NUS ppl around?

  you also NUS de? engin also arh?
  
  btw watching one piece during lectures might be a good idea to distract others and not fall asleep
• papercut87

  15 Jan 07, 13:55

  yup. fellow NUS here. =)
• missallsunday

  15 Jan 07, 16:26

  Originally posted by hisoka:

  you also NUS de? engin also arh?
  
  btw watching one piece during lectures might be a good idea to distract others and not fall asleep

  yep i also from nus engine =p
• lpx88

  15 Jan 07, 17:26

  o.O i just learnt basic differentiation in sec 4 a maths then i see dy/dx thought its a differentiation question
• popikachu

  15 Jan 07, 18:27

  hmmm....
  
  what math is this?
  
  sec 2? 3? jc? poly?
  
  i think is sec 1 or 2 bah...
  
  cus i didnt see this question yet...
  k i top in maths in my class... i try help you...
• popikachu

  15 Jan 07, 18:30

  x + y + 1 + ( -x + y - 3 )(dy/dx) = 0
  
  find the general soln.
  

  what is that?
  (dy/dx)
  
  i think this one not secondary sch maths ahh... cus i dont even understand...
  
• papercut87

  15 Jan 07, 18:31

  haha its uni maths homework..
• hegu

  15 Jan 07, 19:48

  what does it mean by 'homogenous equation' in case of differential eqns?
  
  how do we see whether the DE is homogenous or not? and if it's not we must make it homogenous to proceed?
• missallsunday

  15 Jan 07, 21:08

  Originally posted by hegu:

  what does it mean by 'homogenous equation' in case of differential eqns?
  
  how do we see whether the DE is homogenous or not? and if it's not we must make it homogenous to proceed?

  example:
  (dy/dx)+p(x)y = r(x)
  if r(x) = 0 it is homogenous 1st order linear DE
  if r(x) not = it is non homogenous 1st order linear DE
  
  Homogenous equations are easier to solve as there are proven methods available. (normal separation of y and x, substitution of y=vx, integrating factor, bernoulli's method for non linear DE.)
• CoolMyth

  15 Jan 07, 21:11

  Okay, guess I'm not needed anymore.
  
  So many fellow xiao shi mei here.
• missallsunday

  15 Jan 07, 21:32

  Originally posted by CoolMyth:

  Okay, guess I'm not needed anymore.
  
  So many fellow xiao shi mei here.

  CoolMyth is also from NUS? Wah din noe so many NUS ppl here
• hegu

  15 Jan 07, 22:16

  oh yeah! that's how you solve 2nd order DEs right?
  
  complementary function is the solution of the homogenous eqn, while particular integral is the substitution that you require if it's not homogenous right?
  
  then you add them up to obtain the genera solution right? correct or not correct or not correct or not?
  
  i think i get it liao...thanks for the explanation, missallsunday. i realised you signed up sgforums just to post this answer
• hisoka

  15 Jan 07, 22:27

  Originally posted by CoolMyth:

  Okay, guess I'm not needed anymore.
  
  So many fellow xiao shi mei here.

  i think only got one lor
• deathscythe99

  15 Jan 07, 23:15

  Originally posted by missallsunday:

  yep i also from nus engine =p

  Yr 1?
  
  MA1506...lol
• missallsunday

  15 Jan 07, 23:29

  Originally posted by deathscythe99:

  Yr 1?
  
  MA1506...lol

  Yep spot on for both haha
  You are also year 1?
• deathscythe99

  24 Jan 07, 00:36

  Originally posted by missallsunday:

  Yep spot on for both haha
  You are also year 1?

  No more le