« previous next »
Pages: 1 ... 19 20 [21] 22 23 ... 32   Go Down

Author Topic: Additional Math Help HERE ONLY...!  (Read 76138 times)

Offline jellybeans

  • ,i'm hungry xB
  • SF Senior Citizen
  • *****
  • Posts: 826
  • Reputation: 837
  • Gender: Female
Re: Additional Math Help HERE ONLY...!
« Reply #300 on: June 07, 2010, 03:46:58 pm »
Quote from: slvri on June 07, 2010, 03:39:25 pm
thats because theyve given you the range for x but the angle whos sine is being taken in the question is x/2-1, not x so whatever angle you find after taking inverse sine will be for x/2-1, not x itself. thats why you have to convert the given range for x to a range for x/2-1
that means for the limits given (0 and 6pi) you divide by 2 to get x/2 and then subtract 1 to get x/2-1 which is the required range
and by the way i gave add math in june 2009 and i gave a level math in june 2010
so yeah just felt like helping others out for the add math exam tomorrow :)
oh and HI ASTAR....remember me?

:o OH, so every range they give you, you have to sub it in the ... thing like (x/2-1) to get the MAX value? does this apply to EVERY equation? thanks again :) :)
Logged
You said I must eat so many lemons cause I am so bitter.

Offline J.Darren

  • SF Geek
  • ****
  • Posts: 405
  • Reputation: 956
  • Gender: Male
Re: Additional Math Help HERE ONLY...!
« Reply #301 on: June 07, 2010, 03:51:31 pm »
Quote from: jellybeans on June 07, 2010, 02:11:31 pm
Helloooo, :D
ummm i need help with Q2 please? :) i can find the first two values but... how do you find the rest? :o and how do you know how many 'values' can fit in within the range?  :-\
THANKS IN ADVANCE ;D
http://img69.imageshack.us/img69/3933/trigonometry.png

This is a good way for those that are not accustomed to radian calculation in attempting these sort of questions ...
Logged
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline BlackBunny103

  • SF Geek
  • ****
  • Posts: 439
  • Reputation: 846
  • Gender: Female
  • Don't use time carelessly. It can't be retrieved.
Re: Additional Math Help HERE ONLY...!
« Reply #302 on: June 07, 2010, 04:06:27 pm »
Guys, can you please explain to me Q1 ON 2009 Paper 2? I don't know how to get the answers as shown in the mark schemes.
Thanxx :D
Logged

Offline J.Darren

  • SF Geek
  • ****
  • Posts: 405
  • Reputation: 956
  • Gender: Male
Re: Additional Math Help HERE ONLY...!
« Reply #303 on: June 07, 2010, 04:13:48 pm »
Quote from: BlackBunny103 on June 07, 2010, 04:06:27 pm
Guys, can you please explain to me Q1 ON 2009 Paper 2? I don't know how to get the answers as shown in the mark schemes.
Thanxx :D
i ) Subsitute x = 0, the range would be greater than e^-1.

ii ) f(x) = e^(x+1)

y = e^(x+1)

ln y = (x+1) ln e

ln y = x + 1

ln x = y + 1

ln x - 1 = y

iii ) the domain of f-1(x) = the range of f(x), i.e. x > e^-1
Logged
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline Dibss

  • Chit-Chatter
  • SF V.I.P
  • ********
  • Posts: 5394
  • Reputation: 61167
  • Gender: Female
Re: Additional Math Help HERE ONLY...!
« Reply #304 on: June 07, 2010, 04:18:11 pm »
Anyone who can upload or send me a link to the O/N 09 papers? I think only the mark schemes are available on FEP and Xtreme Papers...
Logged

Offline J.Darren

  • SF Geek
  • ****
  • Posts: 405
  • Reputation: 956
  • Gender: Male
Re: Additional Math Help HERE ONLY...!
« Reply #305 on: June 07, 2010, 04:19:08 pm »
Logged
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline Dibss

  • Chit-Chatter
  • SF V.I.P
  • ********
  • Posts: 5394
  • Reputation: 61167
  • Gender: Female
Re: Additional Math Help HERE ONLY...!
« Reply #306 on: June 07, 2010, 04:21:20 pm »
Logged

Offline BlackBunny103

  • SF Geek
  • ****
  • Posts: 439
  • Reputation: 846
  • Gender: Female
  • Don't use time carelessly. It can't be retrieved.
Re: Additional Math Help HERE ONLY...!
« Reply #307 on: June 07, 2010, 04:24:12 pm »
Quote from: J.Darren on June 07, 2010, 04:13:48 pm
i ) Subsitute x = 0, the range would be greater than e^-1.

ii ) f(x) = e^(x+1)

y = e^(x+1)

ln y = (x+1) ln e

ln y = x + 1

ln x = y + 1

ln x - 1 = y

iii ) the domain of f-1(x) = the range of f(x), i.e. x > e^-1

Thanxx Darren ;). +rep
But I don't understand why from going   ln y = (x+1) ln e  to ln y = x + 1 why did you cancel lne but still keep ln e?
And why is the domain of f-1(x) = the range of f(x) ?
Thanxx again :D
Logged

Offline J.Darren

  • SF Geek
  • ****
  • Posts: 405
  • Reputation: 956
  • Gender: Male
Re: Additional Math Help HERE ONLY...!
« Reply #308 on: June 07, 2010, 04:27:16 pm »
Quote from: BlackBunny103 on June 07, 2010, 04:24:12 pm
Thanxx Darren ;). +rep
But I don't understand why from going   ln y = (x+1) ln e  to ln y = x + 1 why did you cancel lne but still keep ln e?
And why is the domain of f-1(x) = the range of f(x) ?
Thanxx again :D
I pretained ln e there just so that you can comprehend what exactly has happened :D

Bear in mind that the inverse of every function is the reflection of the original function on the line y = x, as we know plugging any value of the range of the original function in a one-to-one equation into its inverse would get us back to where we strated from ...
Logged
Do not go where the path may lead. Go instead where there is no path and leave a trail.

Offline BlackBunny103

  • SF Geek
  • ****
  • Posts: 439
  • Reputation: 846
  • Gender: Female
  • Don't use time carelessly. It can't be retrieved.
Re: Additional Math Help HERE ONLY...!
« Reply #309 on: June 07, 2010, 11:39:53 pm »
Guys would you please help me out with these permutation & combination questions?
Thanxx ;)

My exam is in 4 hours :-\ ...
Logged

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Additional Math Help HERE ONLY...!
« Reply #310 on: June 07, 2010, 11:45:22 pm »
letter M is selcted so in fact you are only choosing 3 from 6C3
Logged

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Additional Math Help HERE ONLY...!
« Reply #311 on: June 07, 2010, 11:47:34 pm »
Since she must select her favourite beatles cd she is only choosing 3 from 8 so 8C3
Logged

Offline BlackBunny103

  • SF Geek
  • ****
  • Posts: 439
  • Reputation: 846
  • Gender: Female
  • Don't use time carelessly. It can't be retrieved.
Re: Additional Math Help HERE ONLY...!
« Reply #312 on: June 07, 2010, 11:54:58 pm »
Quote from: astarmathsandphysics on June 07, 2010, 11:45:22 pm
letter M is selcted so in fact you are only choosing 3 from 6C3

Oh right, this makes sense. Thanxx :D



Quote from: astarmathsandphysics on June 07, 2010, 11:47:34 pm
Since she must select her favourite beatles cd she is only choosing 3 from 8 so 8C3
I understand the concept, but I'm thinking since she's selecting 4 from 9 and there are 4 beatles cs in total, so what if all of her selections contain 4 Beatles CD? What I did was 9C4.
Logged

Offline astarmathsandphysics

  • SF Overlord
  • *********
  • Posts: 11271
  • Reputation: 65534
  • Gender: Male
  • Free the exam papers!
Re: Additional Math Help HERE ONLY...!
« Reply #313 on: June 08, 2010, 12:01:57 am »
her FAVOURITE beatles cd so remove one from the selection sincve this is taken
Logged

Offline BlackBunny103

  • SF Geek
  • ****
  • Posts: 439
  • Reputation: 846
  • Gender: Female
  • Don't use time carelessly. It can't be retrieved.
Re: Additional Math Help HERE ONLY...!
« Reply #314 on: June 08, 2010, 12:48:16 am »
I need help with this question, how can you find a?
Thanxx :D
Logged
Pages: 1 ... 19 20 [21] 22 23 ... 32   Go Up
« previous next »