## gary's Content

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### #9200Struggling

Posted by on 12 November 2004 - 05:15 PM in Mathematics

Well I was struggling but I passed my NAB with

6/6
5/8
15/16
3/4

So I was very happy.

### #9201NABS

Posted by on 12 November 2004 - 05:19 PM in Other

Higher Chemistry - 22/30 Pass
Higher History - Britain - Pass
Higher English - Textual Analysis - 18/30 - Pass
Higher Physics - 27/30 - Pass
Higher Maths - 6/6
5/8
15/16
3/4 Pass

### #9202Most demanding subject

Posted by on 12 November 2004 - 05:24 PM in General Chat

Last year would have been Higher French but I ended up not sitting the exam, the whole course is basically crap and too high a jump from Standard Grade compared to any other subject.

This year probably Higher Chemistry.

### #9255Differentiation

Posted by on 13 November 2004 - 10:52 PM in Mathematics

The blue triangle electrical company issues a black tool case to each of its employees. For publicity purposes it decides to attack a blue plastic triangle to the outside of each case.

In the diagram the rectangle ABCD represents the outside of the case which measures 40 cm by 30 cm. The triangle within the rectangle represents the blue plastic triangle which is placed so that the lengths of the lines AE and DF are x centimetres and 2x centimetres respectively.

A show that the area S square centimetres of the triangle CEF is given by s(x) = 600 - 30x x x2

(b) Show the interval of values of x on which the function s(x) is defined.

© use calculus to find the greatest and least possible values for the area of triangle cef.

peakland plastics manufacture food containers which have a square base and are cuboid in shape. The sides and base are made of rigid plastic and the lid is made of flexible plastic. the company decide to add a new size of container to this range. it is to have a volume of 4000 cubic centimetres.

(a) if x centimetres is the length of each edge of the base of this container. show that the total area h centimetres of the rigid plastic used is given by

h = x2 + 16000/x

(b) find the dimensions of the container which ensure that the minimum possible area of rigid plastic is used.

### #9265Differentiation

Posted by on 14 November 2004 - 03:18 PM in Mathematics

Thanks for helping me with this, I think the bit I got stuck at was.

x3 = 8000
x = 20

How do you get 20 from that?

### #9369Most demanding subject

Posted by on 16 November 2004 - 07:27 PM in General Chat

I heared about a school that tried the int two thing in 4th year for subjects and a huge majority of people ended up with no award. It is a stupid thing to do if some people in 5th year can't even achieve and int two.

### #9401Gmail

Posted by on 16 November 2004 - 11:02 PM in General Chat

Hey can you send me an invite

### #9861Ucas Forms

Posted by on 23 November 2004 - 07:18 PM in Course Choices

I handed my UCAS form in way back in October and I have still not got any confirmation they have recieved it should I be worried.

### #9867Ucas Forms

Posted by on 23 November 2004 - 07:49 PM in Course Choices

I don't even know who my referee is my school is so slow and crap.

### #10578Help With Questions

Posted by on 04 December 2004 - 10:46 AM in Chemistry

Which of the following is not true about benzene?

A It can decolourise bromine water
B All of the c-c bond lengths are equal
C It does not really undergo addition reactions
D The electrons in benzene are delocalised

When ethylbenzene is converted to phenylethene what is the reaction called?

A Reduction
B Dehydrogenation
C Dehydration
D Polymerisation
E Reforming

A compound C7 H12 02 reacts with sodium carbonate solution liberating carbon dioxide gas, and it also decolourises bromine water rapidly. What would be its structural formula.

The next two questions might be hard to understand as they are one of the grid questions.

How is and alcohol H-C-C-O-H produced from CH2 double bond CH2?

How would you convert and alcohol H-C-C-O-H into an addition bromine reaction (2 steps required)

Thanks for any help.

Posted by on 04 December 2004 - 10:54 AM in Mathematics

R = 50x - x2 - 475

Rewrite R in the form a(x-p)2 + q by completing the square. stating the values of a,p and q clearly.

Hence state the maximum value of R and the corresponding value of x.

Complete the square on the expressions -x2 - 4x + 1

Hence show that, for the curve with the equation y= -1/3xcubed - 2xsquared + x -7, the gradient of the tangent cannot be greater than 5.

State the value of x for which the gradient of the tangent equals 5.

Thanks for any help.

### #10581 What do you think you will get in the final exam?

Posted by on 04 December 2004 - 10:56 AM in Mathematics

It's hard to tell this early on and the exam questions are always really hard so I will wait until the prelim before even having an idea of what I wil get.

Posted by on 05 December 2004 - 01:56 PM in Mathematics

Thank You

### #10664Help With Questions

Posted by on 05 December 2004 - 02:00 PM in Chemistry

Thank You

Posted by on 05 December 2004 - 03:16 PM in Mathematics

I know you are probably right but when I do the differentiation I get

-x(^2) - 4x + 1.

I'm still confused with the first question this is how I have done it:

-1 ( x(^2) - 50x - 475)
-1 ( (x-25)squared - 475 - 25(^2)
-1 ( (x-25)squared - 475 - 625)

1100 (x-25)squared

Thanks if you help again I'm just confused by the whole quadratic topic.

Posted by on 05 December 2004 - 03:51 PM in Mathematics

Thanks I've got it now

### #11530Straight Line Geometry Problem

Posted by on 21 December 2004 - 07:18 PM in Mathematics

P,Q,R and S have coordinates (13,5) (3,7) and (5,-3) respectively and are three vertices of a rhombus PQRS.

Find the equations of PS and QS

Hence find the oordinates of the fourth vertex S

Thanks for any help.

### #12469Differentiation Problem

Posted by on 22 January 2005 - 01:16 PM in Mathematics

Find the x-coordinate of each of the points on the curve y= 2x3 - 3x2 - 12x + 20 at which the tangent is parallel to the x-axis.

Also if anyone has past papers can you help me with the following:

1993 paper 1 Q8
1993 paper 1 Q10
1993 paper 1 Q 11

Posted by on 22 January 2005 - 01:19 PM in Revision and Exams

How can people achieve four A's and a B and STILL complain.

### #12494Differentiation Problem

Posted by on 22 January 2005 - 02:41 PM in Mathematics

Thanks thats actually very easy.

I can do most of these questions it is just trying to figure out tangent problems and what topic they are related to.

I would post the 1993 questions but they all involve graphs so it is too difficult to explain.

### #12499Differentiation Problem

Posted by on 22 January 2005 - 05:53 PM in Mathematics

Thank You

I will go over them now to see if I can understand them.

### #12501Differentiation Problem

Posted by on 22 January 2005 - 05:58 PM in Mathematics

Can you help with questions 10 and 11 because I totally don't get them.

### #12502Differentiation Problem

Posted by on 22 January 2005 - 06:04 PM in Mathematics

In question 11 I understand up until the Integration bit I just don't know what you do after that.

### #12708Critical Essays

Posted by on 26 January 2005 - 05:54 PM in English

45 minutes for the essay is fine if you know the text and the amount of times it is gone over in class you should then 45 minutes should be more than enough.

### #12709stress for exams

Posted by on 26 January 2005 - 05:57 PM in Mathematics

The only thing that bothers me about maths is that the NABs are so easy and there is never any time to do harder examples in class like there is in other subjects. So you basically have no chance of passing the exam unless you spend hours doing past papers at home.