Recent content by roman93

If every continuous function on M is bounded, what does this mean? I am not sure what this function actually is... is it a mapping from M -> M or some other mapping? Is the image of the function in M? Any help would be greatly appreciated!

Ah okay, thank you both very much for your help!

okay E = hc/λ. so using a wavelength of 570nm I get that E = 3.49*10^-19 J. so the number of photons = (1.02*10^-20)/3.49*10^-19 which is 0.03... I think somewhere I went wrong but can't figure out where?

can you check that I have calculated the flux right? m_1 = 31, m_2 = -26.8, f_1 = ? and f_2 = 1350. 31+26.8 = -2.5log(f_1 / 1350) so 10^(-57.8/2.5) = f_1/ 1350 so f_1 = 1350*10^(-57.8/2.5)

Oh perhaps... I calculated the flux wrong then. Because using a wavelength of 570nm I get the energy per photon to be higher than the flux. so surely I can't have almost 0 photons reaching earth?

guess I just divide one by the other. How do I work out the energy given the flux? (The total energy would be luminosity right?) if so the formula f = L / 4(pi)d^2 is the diameter the object receiving or the one emitting?

Homework Statement The faintest objects that have been detected at optical wavelengths with the Hubble Space Telescope have apparent magnitudes m  31. Calculate the flux from an object of this magnitude, and, assuming that each photon has a typical optical wavelength, convert your result...

Im(A) is Image(A) or the space that we get when we apply the linear transformation S to A. Also T' is the same transformation as T but just on a different domain. I guess what I wrote in OP was wrong, but is it fine to say that Image(T') = Image(TS), so Rank(T') = Rank(TS) ?

let S: A ->B and T: B -> C be linear maps. Then TS : A -> B -> C. But am I right in thinking that the map T': Im(A) -> C is the same as TS? If this is wrong, can you explain why please :) Thanks very much in advance!

I think I know where I went wrong, what I should be doing is finding an upper bound for 1/x rather than a lower bound. The answer I now have is 5/21 and this seems to work. If I have gone wrong somewhere, please do point it out =]

Hey guys, I found this question and it started bugging me: find the _largest_ δ such that |x - 5| < δ => |1/x - 1/5| < 1/100. This is what I did to try solve the question: From |1/x - 1/5| < 1/100 : I got 1/x > 19/100 and so I wanted x < 100/19 plugging that back into the first...

Do you think I will be able to get a job in engineering with a Math degree?

I don't really mind, just provide some sort of service so that it solves their problems and makes them happy

Hello guys, I am currently in my first year of studying maths and well... I thought I enjoyed it in the first term... but I really don't see the point of learning it anymore. I want to help other people and I am not sure how I am going to do this with a Math degree. I don't have any...