Stephen S

If you have the equation of a 3d line, say 3i+4j+4k + λ(i+2j+7k), how do you find an alternative equation for it, such that the position vector is perpendicular to the direction vector?

Any help would be really appreciated!

I've been told I have to use integration by substitution. Any help would be really appreciated.

Thanks!

2√(−x) − (r²−x) / r = 0

any help will be really appreciated!

Hi everyone, would really appreciate some help with these questions, they seem intuitive but I really have no idea how to work them.

1. Given that A is a subset of B, prove that AnC is a subset of BnC

2. Given that AnB' is a subset of B, prove A is a subset of B

3. Given that A is a subset of B, prove that AnB' is a subset of B

Would really appreciate help on this because this is in for tomorrow and none of my books are any help!

Thank you, all answers will get a thumbs up!

x/(x+3) is greater than 1/(x-2)

any help is really appreciated, got my exam tomorrow

5(2^x)=5^2x

help is really appreciated, got my exam tomorrow

how do you solve x^1.5 =1/6 with no calculator

having a bit of a crisis here, any help is so, so appreciated right now

thanks for any help!!!!

has anyone got some examples of important discoveries that have been made by trial and error, or simply by accident?

The only ones I have so far are penicillin, and the rutherford model of the atom.

Any help is really appreciated!

Hi everyone!

I have been searching on the internet but I haven't been able to come across the first experiment/theory which suggested that electrons act like waves. Does anyone have this knowledge?

any help is really appreciated

In a scientific study, the size, P of a particular population at time t hours is being studied. Initially P = 560 and after 6 hours P is found to be 1218. In a simple model of the population growth, the rate of increase of the population is taken to be proportional to the population at that time.

Using this model, predict the size of the population after 24 hours

x/(x-3) is greater than 1/(x-2)

the problem I think I'm having is that when cross multiplying, when the (x-3) or (x-2) is negative, the inequality switches around. It's quite frustrating because i used to be able to do this, but ive just forgotten it haha.

any help is really appreciated.

6 tan x - sec^2 x = 7

any help really appreciated :)

Using the discriminant, formula b^2 - 4ac, can you help me solve this problem please

Find the values of c for which the line y = x + c is a tangent to the curve x^2 +xy + 2 = 0

Any help would be really appreciated.

I have 2 sets of x y scatter data. I can present them on two separate graphs but does anyone know if there is a way of combining the data on to one?

this is an example of the sort of data I have

x y x y

0 1 10 3

1 5 9 6

2 3 8 9

(these are just example numbers)

MgO

Al2 O3

P4 O6

Write equations to demonstrate the acid-base properties of each compound.

Any help will be really appreciated, all answers will get a thumbs up!!

Thank you!!

H2CC(CH3)CHCH2

If you could also explain to me how you figure it out that would be very useful. I understand the principles behind these types of bond, but I don't get how this molecule would really work, as especially at the beginning, why would H2 bond onto something when it already has a full outer shell???

Any help would be really appreciated, everyone will get a thumbs up!

Thank you!!

a) C-H bond in methane, CH4

b)C=O bond in Carbon dioxide, CO2

c)C-C bond in ethane, C2H6

d)C-C in ethanol, C2H5OH

any explanation would be very appreciated if you have time.

Thank you!!

a) AL (s)

b) Al2 O3 (l) (just seperated it out to make it clearer)

c) KCl (aq)

d) HCl (g)

explanation would be extremely useful if you have time

Thank you!!

Equal amounts of four substances are added to separate samples of 100cm^3 of water. Which solution has the highest pH?

a) NaCl

b) AlCl3

c) PCl3

d)Cl2

explanation would be helpful, if you've got time

Thank you!

Hi, I'm only about a term through the IB, not sure doing it was the right choice, but that's another topic. Anyway, we've been told that we need to have registered our topic and question for the extended essay by mid December, and I was looking for a bit of advice.

I want to do it on Economics, as I enjoy it and am thinking about doing it at university. My idea at the moment would be something along the lines of "How and why did John Cowperthwaite's economic ideas and principles spread through Asia and Eastern Europe".

http://en.wikipedia.org/wiki/John_James_Cowperthwa... - gives a decent, very brief explanation of what he did. There are lots of other sites I could use for info by the way

I got the idea after watching "Britain's Trillion Pound Horror Story" a couple of weeks ago.

For those of you who are doing/have done the extended essay, does this seem like a decent title? Have you got any advice on how I could change it slightly, or if it's rubbish, could you suggest some other economics related titles, or a theme for one?

Having only studied economics for a term, I don't know a lot about the subject yet, but we're not writing it for quite a long time yet so that's not a problem.

If you're interested, these are my subjects: Higher: Economics, Maths, Chemistry. Standard: English, French, History