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## gary's Content

There have been 535 items by gary (Search limited from 29-November 21)

### #23646 2001 Paper 1 Q. 10

Posted by gary on 16 May 2005 - 01:34 PM in Problem Questions

### #10580 Quadratics Questions

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

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.

### #9265 Differentiation

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

x3 = 8000

x = 20

How do you get 20 from that?

### #25176 Help

Posted by gary on 19 May 2005 - 06:47 PM in Mathematics

### #25174 Help

Posted by gary on 19 May 2005 - 06:43 PM in Mathematics

Thanks.

### #24125 LOGS!

Posted by gary on 17 May 2005 - 08:04 PM in Mathematics

let x = log base 2 3

then 2 power x = 3

log e 2 power x = log e 3

x= ln3/ln2

I'm sorry if you can't understand this I can't get to work the icon thingys.

Basically you use this method for the first three.

### #10578 Help With Questions

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

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.

### #7701 Help with recurrence relations question

Posted by gary on 21 October 2004 - 06:27 PM in Mathematics

### #7697 Help with recurrence relations question

Posted by gary on 21 October 2004 - 05:17 PM in Mathematics

of the harmful

''Aquatec''was found to kill 98 percent of the harmful Bacteria present but another 2450 new Bacteria appeared daily.

''Magiclean'' was found to kill 96 present but another 2400 new Bacteria appeared daily.

Compare the effectiveness, in the long-term, of these two products as far as the eradication of harmful bacteria is concerned.

### #16051 Extended Essay Question

Posted by gary on 13 March 2005 - 02:06 PM in History

My essay is currently at 2,000 words and my teacher still wants me to add in stuff about the Anschluss and the Czech Crisis. If I do this my essay will most likely go to about 2,500 which I think is far too much.

### #24127 LOGS!

Posted by gary on 17 May 2005 - 08:08 PM in Mathematics

x log base 10 2 = logg base 10 1000

x= log base 10 2/log base 10 1000

### #25161 Help

Posted by gary on 19 May 2005 - 06:09 PM in Mathematics

The function x^3-3x+2

find the co-ordinates of a,b,c

find the coordinates of the stationary point d and confirm its nature.

The functions f and g are given as:

f(x) = 4/x-2 and g(x) x+2

what is g(f(x))

Two functions, f and g are definded as follows:

f(x) = x-1 g(x) 1/x^2-1

find g(f(x)

### #6886 Help!

Posted by gary on 09 October 2004 - 09:28 AM in Chemistry

Can someone help me with these questions please:

**An element has the electron arrangement 2,8,18,18,8,2**

What will the main type of bonding be between its atoms?

Why does this electron have a higher boiling point thatn its neighbour with an electron arrangement 2,8,18,18,8,1?What will the main type of bonding be between its atoms?

Why does this electron have a higher boiling point thatn its neighbour with an electron arrangement 2,8,18,18,8,1?

**CH4 and CF4 are both polar molecular compounds in which the moclecules both have the same tetrahedral shape.**

**Which would you expect to have the higher boiling point and why?**

The HCF3 molecule also has a tetrahedral shape and its boiling point is higher than that of CH4 and CF4. Suggest a reason for this.The HCF3 molecule also has a tetrahedral shape and its boiling point is higher than that of CH4 and CF4. Suggest a reason for this.

Silicon dioxide and carbon dioxide have similar names and similar formulae. Yet these two compounds are very different in their properties.

Explain in terms of bonding and structure why silicon is a high melting point solid and carbon dioxide is a gas at room temperature.

SiO2 CO2Silicon dioxide and carbon dioxide have similar names and similar formulae. Yet these two compounds are very different in their properties.

Explain in terms of bonding and structure why silicon is a high melting point solid and carbon dioxide is a gas at room temperature.

SiO2 CO2

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