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Had a few more questions regarding probability, if someone can help me (please): For the first one: very that this function f is a probability density, that is, that: f(x) is greater than or equal to zero and \int_{-\infty}^{\infty}f(x)dx = 1 Thanks

A pure substance is a material that is composed of only one type of particle; examples of a pure substance include gold, oxygen and water. A mixture is made of more than one type of particle, so it is impure

Alright: 3) In Ancient Greece, Ptolemy was one of the first who attempted to create a model of the universe. This model was mainly created in order to explain the motion of heavenly bodies according to the Greek's understanding, and also to refine the model of the Greek astronomers before them...

Umm, aren't they meant to be short answers...

Thanks, so sub your data into the formula: v = 67.8 * 12.5 = 847.5km/s

That's a typo.

1) Assuming you're familiar with the Doppler effect, objects that are moving away from you tend to have a longer wavelength than objects that are stationary. This means that the red shift in galaxies (means that the light they release is red-shifted which has a longer wavelength than most other...

Which ones lol?

do you mean these?

Sorry for the typo, its meant to be o(2-) not P(2_0

Rusting is also a redox reaction, where iron is oxidised (loses electrons), which are transferred to oxygen to create O^(2-). The Fe(2+) and P(2_0 combine to form ferrous oxide, aka rust

No worries :)

Think about it this way: the hydroxide ion has a negative charge (hence it has 1 excess electron). So two hydroxide ions would have a charge of -2 (2 extra electrons). When the 2 hydroxides bond with zinc (which has no extra electrons and so a charge of 0), zinc gives away 2 of its electrons and...

Oxidation and reduction aren't two separate reactions: they are 1 reaction, called a redox reaction. So, like in every chemical reaction, the atoms of different elements/compounds rearrange themselves and form new elements compounds. This is done mainly by swapping electrons. Oxidation and...

Guess InteGrand beat me to it lol

Notice that this is a geometric series with factor r = x, first term a = 1 and has 2n terms: Chuck this into the formula And yeah you got yourself a formal proof!

No worries :D

Right thanks I'll get back to you on that question. Any thoughts on the other one?

IG any thoughts on these q's?

When going from my second to the third line, I just substituted in the stuff from part (a) wherever I could, like dr/dx = cos (theta) etc. (excuse my d/dx's in this reply, they're meant to be partial)