Author Topic: I need urgent help  (Read 1582 times)

Offline cs

  • SF Immigrant
  • **
  • Posts: 106
  • Reputation: 264
  • Gender: Female
I need urgent help
« on: October 07, 2010, 09:58:21 am »
Exam is on this coming wednesday for Maths CIE AS level,

Can anyone explain to me question 9iii, why the find the gradient and inverse tangent?

picture attached.

Its Nov 2008 Paper 1 CIE AS level by the way.

Thank you!

Freaked12

  • Guest
Re: I need urgent help
« Reply #1 on: October 07, 2010, 11:21:13 am »
Gradient of a line is also defined as the tangent of the angle which a line makes with the +ve direction of x axis.
If gradient is +ve, angle made is acute and if gradient is -ve, angle made is obtuse

Offline S.M.A.T

  • SF Master
  • ******
  • Posts: 1595
  • Reputation: 18522
  • Gender: Male
Re: I need urgent help
« Reply #2 on: October 07, 2010, 01:10:31 pm »
Exam is on this coming wednesday for Maths CIE AS level,

Can anyone explain to me question 9iii, why the find the gradient and inverse tangent?

picture attached.

Its Nov 2008 Paper 1 CIE AS level by the way.

Thank you!
what did u mean by that ???................did u mean that when they calculate the angle why did they inverse the gradient ???


"A man's life is interesting primarily when he has failed - I well know. For it's a sign that he tried to surpass himself." Clemenceau, Georges

Offline Deadly_king

  • <<Th3 BO$$>>
  • Global Moderator
  • SF Farseer
  • *****
  • Posts: 3391
  • Reputation: 65078
  • Gender: Male
  • Hard work ALWAYS pays off.........just be patient!
    • @pump_upp - best crypto pumps on telegram !
Re: I need urgent help
« Reply #3 on: October 07, 2010, 06:12:00 pm »
Exam is on this coming wednesday for Maths CIE AS level,

Can anyone explain to me question 9iii, why the find the gradient and inverse tangent?

picture attached.

Its Nov 2008 Paper 1 CIE AS level by the way.

Thank you!

Hmm.........you need to find the gradients so that you can find the equations of the lines of the two tangents.

Then you solve both equation simultaneously to find the point of intersection. Let R be the point of intersection.

Using the coordinates, you'll then be able to find the magnitude/length of the sides of the triangle PQR which will allow you to calculate the acute angle between the two tangents.

Hope you get me :)

Offline S.M.A.T

  • SF Master
  • ******
  • Posts: 1595
  • Reputation: 18522
  • Gender: Male
Re: I need urgent help
« Reply #4 on: October 07, 2010, 08:43:53 pm »
Here is a short method......no need to write whose sentences that i have written.I wrote those lines to make you understand
i hope that helps :)

DK:don't u think that your method is a bit lengthy for 4 marks ? ::)


"A man's life is interesting primarily when he has failed - I well know. For it's a sign that he tried to surpass himself." Clemenceau, Georges

Freaked12

  • Guest
Re: I need urgent help
« Reply #5 on: October 07, 2010, 09:02:31 pm »
He wanted the solution or the reason behind finding the gradient.  :o
« Last Edit: October 07, 2010, 09:14:06 pm by Requiem »

Offline S.M.A.T

  • SF Master
  • ******
  • Posts: 1595
  • Reputation: 18522
  • Gender: Male
Re: I need urgent help
« Reply #6 on: October 07, 2010, 09:30:57 pm »
He wanted the solution or the reason behind finding the gradient.  :o


the reason is given in my solution ::)
« Last Edit: October 07, 2010, 09:32:38 pm by asiftasfiq93 »


"A man's life is interesting primarily when he has failed - I well know. For it's a sign that he tried to surpass himself." Clemenceau, Georges

Offline cs

  • SF Immigrant
  • **
  • Posts: 106
  • Reputation: 264
  • Gender: Female
Re: I need urgent help
« Reply #7 on: October 08, 2010, 02:34:27 am »
Thanks asiftasfiq93 for the detailed workings. I have a question, is that a fixed method, like its always using tan instead of sin and cos? I have seen a few question and they all used tan in the mark scheme..

Offline Deadly_king

  • <<Th3 BO$$>>
  • Global Moderator
  • SF Farseer
  • *****
  • Posts: 3391
  • Reputation: 65078
  • Gender: Male
  • Hard work ALWAYS pays off.........just be patient!
    • @pump_upp - best crypto pumps on telegram !
Re: I need urgent help
« Reply #8 on: October 08, 2010, 04:55:28 am »
Here is a short method......no need to write whose sentences that i have written.I wrote those lines to make you understand
i hope that helps :)

DK:don't u think that your method is a bit lengthy for 4 marks ? ::)

Hmm......yeah I guess it IS long. Sorry for the confusion.

Actually I was in a rush yesterday, so I just pointed out what was in my mind. Didn't have much time to think about it  :D

Good job Asif.....+rep  :)

By the way Requiem.......cs is a she  ;)
« Last Edit: October 08, 2010, 04:59:02 am by Deadly_king »

Offline Deadly_king

  • <<Th3 BO$$>>
  • Global Moderator
  • SF Farseer
  • *****
  • Posts: 3391
  • Reputation: 65078
  • Gender: Male
  • Hard work ALWAYS pays off.........just be patient!
    • @pump_upp - best crypto pumps on telegram !
Re: I need urgent help
« Reply #9 on: October 08, 2010, 05:03:09 am »
Thanks asiftasfiq93 for the detailed workings. I have a question, is that a fixed method, like its always using tan instead of sin and cos? I have seen a few question and they all used tan in the mark scheme..

Yeah.........tan is always used when involving tangents  ;)

Offline cs

  • SF Immigrant
  • **
  • Posts: 106
  • Reputation: 264
  • Gender: Female
Re: I need urgent help
« Reply #10 on: October 08, 2010, 05:33:16 am »
lol @ deadly king, i even double check the "gender" icon at the side, its female.  :D

Thanks to all! I understood now.  *Luckily i realize them before going to exam* +REP

Offline cs

  • SF Immigrant
  • **
  • Posts: 106
  • Reputation: 264
  • Gender: Female
Re: I need urgent help
« Reply #11 on: October 08, 2010, 05:37:27 am »
I have tried 3 times to +rep to asif, but error kept on occurring. not sure why.

Offline Deadly_king

  • <<Th3 BO$$>>
  • Global Moderator
  • SF Farseer
  • *****
  • Posts: 3391
  • Reputation: 65078
  • Gender: Male
  • Hard work ALWAYS pays off.........just be patient!
    • @pump_upp - best crypto pumps on telegram !
Re: I need urgent help
« Reply #12 on: October 08, 2010, 05:40:35 am »
lol @ deadly king, i even double check the "gender" icon at the side, its female.  :D

Thanks to all! I understood now.  *Luckily i realize them before going to exam* +REP

I guess you need to spread the love first (wait for two hours)

HAhaha..........Requiem was not very attentive :P

Wish you good luck for exams.........Am sure you'll ace them all :)

Offline S.M.A.T

  • SF Master
  • ******
  • Posts: 1595
  • Reputation: 18522
  • Gender: Male
Re: I need urgent help
« Reply #13 on: October 08, 2010, 09:52:12 pm »
thanks DK :D

Thanks asiftasfiq93 for the detailed workings.

u welcome :D
« Last Edit: October 08, 2010, 10:36:20 pm by asiftasfiq93 »


"A man's life is interesting primarily when he has failed - I well know. For it's a sign that he tried to surpass himself." Clemenceau, Georges