Post by: Mao on November 09, 2010, 12:35:05 pm
That was a really difficult exam. So it's not the end of the world, you guys can take a chill pill and now GO STUDY FOR CHEM.
Post by: chopz on November 09, 2010, 01:27:34 pm
If not, I guess I will after I get up. You have ~30mins before I start. :)
I think we all trust your answers :) good man.
Post by: 3Xamz on November 09, 2010, 01:27:46 pm
Some people said they would but noones published anything.
+Karma if you can post it sometime soon :)
Cheers
Post by: Mao on November 09, 2010, 04:07:21 pm
Post by: 3Xamz on November 09, 2010, 04:11:54 pm
Post by: lorcan_raven on November 09, 2010, 04:22:53 pm
I can now sleep.
Post by: axilon on November 09, 2010, 04:35:05 pm
quick question, for the expected number of statues, how many marks out of 4 would i get if i used the wrong p value,
for some reason i used 0.7 not 0.75 even though it was given, ultimately i got E(x)=1.1??
thanks in advance =D
Post by: lorcan_raven on November 09, 2010, 04:46:29 pm
Post by: johnson on November 09, 2010, 04:49:52 pm
Post by: axilon on November 09, 2010, 04:50:25 pm
didn't know they had hearts?? =]
thanks man.
Post by: stonecold on November 09, 2010, 04:50:48 pm
Looking at the last two sections of Q2, they were probably fair game.
Under the pressure of the exam I had no idea what I was doing but they weren't really that hard. Just need to think outside the square a little.
Got completely shit on for the last question though. CAS kept on spitting out errors, and I just left most of the questions with gibberish workings...
Post by: 98.40_for_sure on November 09, 2010, 04:52:46 pm
Great, another mark gone. Guessed the number of S.Ps as 3, because it was quartic lol.
Haha same. I immediately thought ooh a quartic *thinks of W shape*
"yes yes yes W means 3 stationary points"
*writes 3*
Assessor: PENS DOWN
"SHIT ITS 2" :(
Post by: cypriottiger on November 09, 2010, 04:55:24 pm
i was tempted to keep going seeing as i was using a pacer... :)
Post by: lisafaustina on November 09, 2010, 05:05:27 pm
Post by: lisafaustina on November 09, 2010, 05:07:19 pm
Post by: lisafaustina on November 09, 2010, 05:09:53 pm
Post by: Whatlol on November 09, 2010, 05:15:06 pm
Post by: Mao on November 09, 2010, 05:19:14 pm
hey with question 2.3e with dT/dx shouldnt it be a negative sign before 12cos(x)^5sin(x) blabla
Nope, that's a positive.
Post by: becca92 on November 09, 2010, 05:34:08 pm
Post by: jane1234 on November 09, 2010, 05:35:30 pm
in 2.4.b did we have to find the coordinates or was x =1/a and x =(1+ab)/4a an adequate answer?
The question just asked for what x-values are there a stationary point, so i dont think co-ordinates were needed ...
Post by: lisafaustina on November 09, 2010, 05:37:30 pm
Post by: luffy on November 09, 2010, 05:52:51 pm
When I entered that dT/dx question into my CAS. I got 2tan^-1 ((root6 - root 2)/root3). Turns out that is the same as cos^-1(1/root3). Will I lose marks? However, when I found the volume, I got a really long answer haha.
Could you guys please tell me how you got the cos^-1 answer. Even when I try it now, I get the same answer. How did you guys do it?
Post by: Mao on November 09, 2010, 05:54:24 pm
^^this. I stated the coordinates for completeness, and also that later parts required the coordinates.in 2.4.b did we have to find the coordinates or was x =1/a and x =(1+ab)/4a an adequate answer?
The question just asked for what x-values are there a stationary point, so i dont think co-ordinates were needed ...
hey mao, what do you reckon the A+ cut off will be?I did say I won't be making a prediction. :)
Post by: jimmy999 on November 09, 2010, 05:54:51 pm
wow - nice solutions.
When I entered that dT/dx question into my CAS. I got 2tan^-1 ((root6 - root 2)/root3). Turns out that is the same as cos^-1(1/root3). Will I lose marks? However, when I found the volume, I got a really long answer haha.
Could you guys please tell me how you got the cos^-1 answer. Even when I try it now, I get the same answer. How did you guys do it?
If the question just asked for an exact answer, then that should be okay. However if it specified what form it needs to be in, then marks can be taken off
Post by: Mao on November 09, 2010, 05:59:11 pm
wow - nice solutions.
When I entered that dT/dx question into my CAS. I got 2tan^-1 ((root6 - root 2)/root3). Turns out that is the same as cos^-1(1/root3). Will I lose marks? However, when I found the volume, I got a really long answer haha.
Could you guys please tell me how you got the cos^-1 answer. Even when I try it now, I get the same answer. How did you guys do it?
It will be accepted. An examiner who runs across this will double check when he/she sees it (if he/she is not an idiot, and they generally tend to be fairly good).
Following the steps of my workings in the solutions, it was just an application of the null factor theorem.
Post by: jayna on November 09, 2010, 06:02:22 pm
Did you find it harder than 07?^^this. I stated the coordinates for completeness, and also that later parts required the coordinates.in 2.4.b did we have to find the coordinates or was x =1/a and x =(1+ab)/4a an adequate answer?
The question just asked for what x-values are there a stationary point, so i dont think co-ordinates were needed ...hey mao, what do you reckon the A+ cut off will be?I did say I won't be making a prediction. :)
*PRAYS* please say yes. By a long shot. *Ends Prayer*
Post by: axilon on November 09, 2010, 06:02:57 pm
wow - nice solutions.
When I entered that dT/dx question into my CAS. I got 2tan^-1 ((root6 - root 2)/root3). Turns out that is the same as cos^-1(1/root3). Will I lose marks? However, when I found the volume, I got a really long answer haha.
Could you guys please tell me how you got the cos^-1 answer. Even when I try it now, I get the same answer. How did you guys do it?
It will be accepted. An examiner who runs across this will double check when he/she sees it (if he/she is not an idiot, and they generally tend to be fairly good).
Following the steps of my workings in the solutions, it was just an application of the null factor theorem.
so if you did use inverse tan etc and u got an extremely large expression for the volume will you still get the marks if its unsimpliflied?
the answer took up a whole line lol.
or are we looking at max 3/4??
Post by: Whatlol on November 09, 2010, 06:16:25 pm
wow - nice solutions.
When I entered that dT/dx question into my CAS. I got 2tan^-1 ((root6 - root 2)/root3). Turns out that is the same as cos^-1(1/root3). Will I lose marks? However, when I found the volume, I got a really long answer haha.
Could you guys please tell me how you got the cos^-1 answer. Even when I try it now, I get the same answer. How did you guys do it?
It will be accepted. An examiner who runs across this will double check when he/she sees it (if he/she is not an idiot, and they generally tend to be fairly good).
Following the steps of my workings in the solutions, it was just an application of the null factor theorem.
so if you did use inverse tan etc and u got an extremely large expression for the volume will you still get the marks if its unsimpliflied?
the answer took up a whole line lol.
or are we looking at max 3/4??
same thing happened to me
Post by: 98.40_for_sure on November 09, 2010, 06:25:23 pm
Post by: TrueTears on November 09, 2010, 06:27:23 pm
Post by: sajib_mostofa on November 09, 2010, 06:40:12 pm
Post by: Blakhitman on November 09, 2010, 06:50:56 pm
BTW for the expected value, I drew up the table and got the values for x=0, and x=1 right, but somehow screwed up x=2 :-\, reckon I could scrape 2/4 marks for that seeing as I did show working to find E(X) and also the table?
Also thank you so much for this, I hope the chem ones are this detailed :P
Post by: Jdog on November 09, 2010, 06:52:05 pm
Post by: sajib_mostofa on November 09, 2010, 06:53:20 pm
SHIT! was the possible x values required in degree form? i left it as .81 and the 1.2 whatever
lol I'm just wondering if you could have it in both forms or does it have to be in radians. You would get the marks but I'm not sure I would since I converted it to degrees.
Post by: Jdog on November 09, 2010, 06:54:23 pm
Post by: Blakhitman on November 09, 2010, 07:01:40 pm
Post by: Jdog on November 09, 2010, 07:09:26 pm
btw for the question where it says find possible values of x in terms of a, b
we only had to give possible values right not the co-ordinate form , ?????
Post by: Mao on November 09, 2010, 07:13:04 pm
Don't predict...but do you reckon lower than 2007? ;)
BTW for the expected value, I drew up the table and got the values for x=0, and x=1 right, but somehow screwed up x=2 :-\, reckon I could scrape 2/4 marks for that seeing as I did show working to find E(X) and also the table?
Also thank you so much for this, I hope the chem ones are this detailed :P
my methods days are so long ago (I did it in 07), I cannot remember what the exam was like.
If I have to rate my distant feelings vs this experience, this one is definitely more calculator intensive. If you didn't know how to navigate calculator errors, or how to use the calculator efficiently, you would have died. In terms of theoretical difficulty and algebraic gayness, this one would also take the crown. Though probability in 07 was definitely a bitch.
Post by: Blakhitman on November 09, 2010, 07:18:15 pm
Don't predict...but do you reckon lower than 2007? ;)
BTW for the expected value, I drew up the table and got the values for x=0, and x=1 right, but somehow screwed up x=2 :-\, reckon I could scrape 2/4 marks for that seeing as I did show working to find E(X) and also the table?
Also thank you so much for this, I hope the chem ones are this detailed :P
my methods days are so long ago (I did it in 07), I cannot remember what the exam was like.
If I have to rate my distant feelings vs this experience, this one is definitely more calculator intensive. If you didn't know how to navigate calculator errors, or how to use the calculator efficiently, you would have died. In terms of theoretical difficulty and algebraic gayness, this one would also take the crown. Though probability in 07 was definitely a bitch.
Cool thanks ( I loved the prob in 07 haha, finding maximums in prob O.o) , I hope to god the A+ is low ;D
Post by: awesome2damax on November 09, 2010, 07:47:08 pm
Post by: lorcan_raven on November 09, 2010, 08:34:44 pm
Will I lose a mark for using tree-diagrams and not Markov chains, but getting the same answers after all?
Post by: sajib_mostofa on November 09, 2010, 08:35:29 pm
Post by: lorcan_raven on November 09, 2010, 08:36:41 pm
Do not know HOW I pulled that outta my ass.
Post by: lorcan_raven on November 09, 2010, 08:41:46 pm
I used tree-diagrams to find the probability of each branch of the sample space,
then added these up into sections of S = 0, 1 or 2. Then from THESE probabilities, I forgot to then multiply them by the S values to get the expected value and just said 2 was the expected value (highest prob)
Will I get 2 or 3 marks for this, out of 4?
Post by: camrenis on November 09, 2010, 08:57:35 pm
Post by: darkphoenix on November 09, 2010, 10:03:35 pm
Post by: sheno on November 09, 2010, 11:30:16 pm
for the tassy jones questions when u have to prove that p=0.75
i just stated the matrix equation and solved it on my calc...
i didn't expand it by hand. the matrix equation counts as working doesn't it?
Post by: sajib_mostofa on November 09, 2010, 11:34:44 pm
thanks man.
for the tassy jones questions when u have to prove that p=0.75
i just stated the matrix equation and solved it on my calc...
i didn't expand it by hand. the matrix equation counts as working doesn't it?
Yeah man
Post by: Blakhitman on November 09, 2010, 11:44:48 pm
I went Pr(SS) +Pr(RS)=0.7
So much quicker than the matrix method (judging by Mao's working out).
Also Mao in that question in your transition matrix, the 2nd row 2nd column should be 1.2-p not 0.8-p...trivial and pointless but thought I'd mention it :buck2:...
Post by: Whatlol on November 10, 2010, 08:36:15 am
I actually didn't use matrix at all for the show p=0.75 question.
I went Pr(SS) +Pr(RS)=0.7
So much quicker than the matrix method (judging by Mao's working out).
Also Mao in that question in your transition matrix, the 2nd row 2nd column should be 1.2-p not 0.8-p...trivial and pointless but thought I'd mention it :buck2:...
yup i did exactly this too
Post by: lizzi on November 10, 2010, 11:59:15 am
Post by: Mao on November 10, 2010, 06:11:34 pm
And thank you for your appreciation. It makes life enjoyable :')
Post by: ulbasour on November 10, 2010, 09:07:12 pm
Same here, just wrote down the matrix equation, and said solve for p, p=.75, if we did that, we wouldn't get dicked a mark for working would we???I actually didn't use matrix at all for the show p=0.75 question.
I went Pr(SS) +Pr(RS)=0.7
So much quicker than the matrix method (judging by Mao's working out).
Also Mao in that question in your transition matrix, the 2nd row 2nd column should be 1.2-p not 0.8-p...trivial and pointless but thought I'd mention it :buck2:...
yup i did exactly this too
Post by: itolduso on November 10, 2010, 10:17:08 pm
Semi-worked solutions. I didn't go into as much detail as enwiabe, but all the key steps are explained.
That was a really difficult exam. So it's not the end of the world, you guys can take a chill pill and now GO STUDY FOR CHEM.
1.21 'A and B mutually exclusive' implies p+q<1
Post by: sajib_mostofa on November 10, 2010, 10:20:00 pm
Semi-worked solutions. I didn't go into as much detail as enwiabe, but all the key steps are explained.
That was a really difficult exam. So it's not the end of the world, you guys can take a chill pill and now GO STUDY FOR CHEM.
1.21 'A and B mutually exclusive' implies p+q<1
Yep Mao stated that it should have been outlined in the Q
Post by: itolduso on November 10, 2010, 10:39:08 pm
Semi-worked solutions. I didn't go into as much detail as enwiabe, but all the key steps are explained.
That was a really difficult exam. So it's not the end of the world, you guys can take a chill pill and now GO STUDY FOR CHEM.
1.21 'A and B mutually exclusive' implies p+q<1
Yep Mao stated that it should have been outlined in the Q
the question as it stands is perfectly ok, you don't need to say p+q<1