Warning: Illegal string offset 'html' in /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php on line 909

Warning: Cannot modify header information - headers already sent by (output started at /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php:909) in /home/hsn/public_html/forum/admin/sources/classes/output/formats/html/htmlOutput.php on line 114

Warning: Cannot modify header information - headers already sent by (output started at /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php:909) in /home/hsn/public_html/forum/admin/sources/classes/output/formats/html/htmlOutput.php on line 127

Warning: Cannot modify header information - headers already sent by (output started at /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php:909) in /home/hsn/public_html/forum/admin/sources/classes/output/formats/html/htmlOutput.php on line 136

Warning: Cannot modify header information - headers already sent by (output started at /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php:909) in /home/hsn/public_html/forum/admin/sources/classes/output/formats/html/htmlOutput.php on line 137

Warning: Cannot modify header information - headers already sent by (output started at /home/hsn/public_html/forum/cache/skin_cache/cacheid_1/skin_topic.php:909) in /home/hsn/public_html/forum/admin/sources/classes/output/formats/html/htmlOutput.php on line 141
THE EXAM! - HSN forum - Page 2

Jump to content


THE EXAM!


30 replies to this topic

#21 ice_illusion

    Child Prodigy

  • Members
  • PipPipPipPipPipPip
  • 947 posts
  • Location:Pluto
  • Gender:Female

Posted 15 May 2007 - 06:09 PM

You can find them in the SQA website, go to mathematics, principal assesors report, then the year. I think 50% was a B and 63% was an A, can't remember what C was.

#22 kingding

    Showing Improvement

  • Members
  • PipPip
  • 37 posts
  • Location:Aberdeen
  • Gender:Male

Posted 15 May 2007 - 06:18 PM

Coolio, cheers dude

#23 paddyb67

    Good Effort

  • Members
  • PipPipPip
  • 66 posts
  • Gender:Male

Posted 15 May 2007 - 08:28 PM

ad absurdum, agreed with all your answers (except 14 which i got wrong) apart from 13b) which i got k = 2, are you pretty confident u were right?

#24 ad absurdum

    Top of the Class

  • Members
  • PipPipPipPipPip
  • 390 posts
  • Location:Cambridge
  • Interests:Muzak.
  • Gender:Male

Posted 15 May 2007 - 08:50 PM

QUOTE(paddyb67 @ May 15 2007, 09:28 PM) View Post
ad absurdum, agreed with all your answers (except 14 which i got wrong) apart from 13b) which i got k = 2, are you pretty confident u were right?
Relatively, but not entirely. What I done:
\sin(2t) \frac{d^2y}{dx^2} + (\frac{dy}{dx})^2 = \sin(2t) (- \csc^3(2t)) + \frac{ \cos^2(2t)}{ \sin^2(2t)}
= \frac{-1}{ \sin^2(2t)} + \frac{(1- \sin^2(2t))}{ \sin^2(2t)}=-1

Which looks like it might be right, but there's a good chance I might have made a mistake somewhere unsure.gif
HMFC - Founded 1874, beefing the Cabbage since 1875

#25 andymckenzie

    Showing Improvement

  • Members
  • PipPip
  • 23 posts
  • Gender:Male

Posted 15 May 2007 - 08:53 PM

thought it was pretty easy to be honest, would doubt if the boundaries went below what they're meant to be

#26 paddyb67

    Good Effort

  • Members
  • PipPipPip
  • 66 posts
  • Gender:Male

Posted 15 May 2007 - 08:56 PM

i think the difference was i worked out d2y/dx^2 by doing d2y/dt^2 divided by d2x/dt^2
which gave d2y/dx^2 as sin(2t)/cos(2t).
maybe thats wrong but i just though with parametric you couldnt just differentiate dy/dx again?

#27 Daron Malakian

    Showing Improvement

  • Members
  • PipPip
  • 21 posts
  • Gender:Not Telling

Posted 15 May 2007 - 09:13 PM

ad absurdum, the derivative of cot(x) is (-cosec2 (x)) so why do you have cosec3(x). Also, it was -cot(x) which was being differentiated so the result would be +cosec2(x).

#28 Daron Malakian

    Showing Improvement

  • Members
  • PipPip
  • 21 posts
  • Gender:Not Telling

Posted 15 May 2007 - 09:29 PM

Does anyone know if the sqa give you marks if you make a mistake at one point and continue it through, using the correct techniques but getting the wrong answers. For example in Q.14 i said k=1, which resulted in both negative growth and height. Thanks.

#29 ad absurdum

    Top of the Class

  • Members
  • PipPipPipPipPip
  • 390 posts
  • Location:Cambridge
  • Interests:Muzak.
  • Gender:Male

Posted 15 May 2007 - 09:43 PM

QUOTE(paddyb67 @ May 15 2007, 09:56 PM) View Post
i think the difference was i worked out d2y/dx^2 by doing d2y/dt^2 divided by d2x/dt^2
which gave d2y/dx^2 as sin(2t)/cos(2t).
maybe thats wrong but i just though with parametric you couldnt just differentiate dy/dx again?
That seems like a very good approach, butI'm not totally sure on if that would work. If you take a simplified view of the chain rule (i.e., "cancelling" on multiplication), that would give you d^2y/d^2x, rather than d^2y/dx^2 - maybe the simplified analogue breaks down here though. However, at t=0, this would give d^2y/dx^2 as 0, when it should be undefined (the parametric equations describe a circle, and the tangent at t=0 is the line x=1, so calculating the rate of change of the gradient at this point should involve division by zero).

What I done was said \frac{d^2y}{dx^2} = \frac{d}{dx}(\frac{dy}{dx}) = \frac{d}{dt}(\frac{dy}{dx}) \frac{dt}{dx}. So you differentiate dy/dx with respect to t, then divide by dx/dt.
HMFC - Founded 1874, beefing the Cabbage since 1875

#30 ice_illusion

    Child Prodigy

  • Members
  • PipPipPipPipPipPip
  • 947 posts
  • Location:Pluto
  • Gender:Female

Posted 15 May 2007 - 10:59 PM

That looks pretty similar to an example in my notes.

I differentiated dy/dt and squared dt/dx then multiplied the answers since I'd forgotten how to do the other thing. whistling.gif I remember looking at the notes, thinking that'll never come up and ignoring it.

#31 loved-up-loon

    Top of the Class

  • Members
  • PipPipPipPipPip
  • 457 posts
  • Interests:Well I like a WIDE variety of things! haha i sound like a freak!<br />Anyways, I LOVE!!! music! ooh sooo much!!<br />haha i also like shopping and ehhm, drama and talking and swimmin(woo look at me aint i fit (not)) and ehhh thats all folks! haha! man i laugh alot! and i can talk for scotland! dont put iot past me i rambol on a lot!!
  • Gender:Female

Posted 16 May 2007 - 10:04 AM

I thought bits of the exam were ok, the rest was horrid though!! I got the roots question to work eventually, took forever cause i kept getting an answer which didnt work. I really hope i passed, i need to get a B!
Grrrrrr!!





1 user(s) are reading this topic

0 members, 1 guests, 0 anonymous users