Need help in Maths! Come in!~ x;

• AugoeideS

  5 Sep 05, 21:43

  1. find the range of values for c for which (2x-1)^2 + 4c^2 > 9 for all real values of x.
  
  2. show that the curve x^2 + y^2 - x(3p+4) - y(p-2) +10p = 0 passes through the point A(3.1) for all values of p.
  
  When p=0, the line y= 2x - 5 intersects the curve at A and B. calculate the coordinates of B.
  
  Thanks in advance!
• Fucking Bitch

  5 Sep 05, 22:01

  Originally posted by AugoeideS:

  1. find the range of values for c for which (2x-1)^2 + 4c^2 > 9 for all real values of x.
  
  2. show that the curve x^2 + y^2 - x(3p+4) - y(p-2) +10p = 0 passes through the point A(3.1) for all values of p.
  
  When p=0, the line y= 2x - 5 intersects the curve at A and B. calculate the coordinates of B.
  
  Thanks in advance!

  for qn1, expand everything out, move all terms to LHS of the inequality, factorise then see from the sketch of the graph of the equation to determine the range that is required by the inequality.
  
  for qn2, sub x=3 into the equation, and you'll see that that the value of y is independent of p (shown). then for the 2nd part, sub y=(2x-5) into the first long long equation. given that x=3, you can find the value of p. then, put this value of p into the equation containing x and p that you have derived earlier. find x.
  
  don't expect people to work out everything for you please.
• sgboy2004

  5 Sep 05, 22:03

  wah... mi O level nia leh
• AugoeideS

  5 Sep 05, 22:13

  FB: Haha, thanks, doesn't need the actual answers lah, but how to get it. Thanks Thanks!
  
  sgBoy2004: Ehhh...Its O level standard.
• kaobeikaobu

  5 Sep 05, 22:14

  Originally posted by sgboy2004:

  wah... mi O level nia leh

  these qns all secondery ones....
• sgboy2004

  5 Sep 05, 22:14

  Originally posted by AugoeideS:

  FB: Haha, thanks, doesn't need the actual answers lah, but how to get it. Thanks Thanks!
  
  sgBoy2004: Ehhh...Its O level standard.

  but mi no take A maths leh
  
  mi topid topid one lah
• jay_rocks

  6 Sep 05, 00:12

  same lvl as mine.
• digicharat

  6 Sep 05, 00:17

  simi lai eh?
  kua bo leh....
  math ah? that subject i hong kan 1 lor....
• hisoka

  6 Sep 05, 00:39

  Originally posted by Fucking Bitch:

  for qn1, expand everything out, move all terms to LHS of the inequality, factorise then see from the sketch of the graph of the equation to determine the range that is required by the inequality.
  
  for qn2, sub x=3 into the equation, and you'll see that that the value of y is independent of p (shown). then for the 2nd part, sub y=(2x-5) into the first long long equation. given that x=3, you can find the value of p. then, put this value of p into the equation containing x and p that you have derived earlier. find x.
  
  don't expect people to work out everything for you please.

  qn2 need to so troublesome meh? just sub y = 1 then solve for x can le mah.. then the second part is jsut simul eqn
  
  qn1 move over to one side factorise and then just test one point on each of the 3 intervals separated by the 2 points and then you will know lor(can do this cos you know the shape of the quadratic curve
• papercut87

  6 Sep 05, 09:13

  Originally posted by AugoeideS:

  1. find the range of values for c for which (2x-1)^2 + 4c^2 > 9 for all real values of x.
  
  2. show that the curve x^2 + y^2 - x(3p+4) - y(p-2) +10p = 0 passes through the point A(3.1) for all values of p.
  
  When p=0, the line y= 2x - 5 intersects the curve at A and B. calculate the coordinates of B.
  
  Thanks in advance!

  1. let y = (2x-1)^2 + 4c^2 - 9 > 0
  since y is positive and doesnt cut x-axis, Discriminant > 0 and find the range
  Do it urself (DIY)
  
  2. sub A (3,1) into y= x^2 + y^2 - x(3p+4) - y(p-2) +10p after which you'll get an equation with all p-s inside, after which you use b² - 4ac and show that the discriminant > 0
  DIY
  
  3. sub p = 0 into y = x^2 + y^2 - x(3p+4) - y(p-2) +10p => y= x^2 + y^2 - x(0+4) - y(0-2) +10p
  then equate them together:
  2x - 5 = x^2 + y^2 - x(0+4) - y(0-2) +10p
  solve simultaneously
  
  DIY.
  
  you'll get two coordinates since its a quad eqn - one of them is A (3,1) and you reject it, the other coordinate will be B.
  
• SBS1908B

  6 Sep 05, 11:43

  Looks familiar.
• $e@wEeD

  6 Sep 05, 16:12

  lol o level emaths
• digicharat

  6 Sep 05, 17:01

  me forgot me o level math liao.