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NSX

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Posts posted by NSX

    Homogeneous vs. Exact (w/ I.F.)

    in Analysis and Calculus

    Posted

    M(x,y)dx +N(x,y)dy=0? i dont get the equation. are you multiplying by differentials dx and dy, or are you trying to say derivative of M wrt x derivative of N wrt y.

     

    Well, I think more precisely, it should be the letter "delta" where "d" goes.

     

    The dx & dy are the partials of some function, F, which has x and y variables in it.

     

    i.e. dF(x,y) = M(x,y)dx + N(x,y)dy

     

    But I think your former statement is the same too.

     

    [edit]

     

    Like the D.E. described here: http://www.efunda.com/math/ode/ode1_exact.cfm

    Homogeneous

    http://www.tau.ac.il/~levant/ode/solution_4.pdf

     

    [edit - 2]

     

    n/m

     

    I remember now that first order D.E. are only homogeneous if they have this property:

     

    f(tx,ty) = t*f(x,y)

    0

    Homogeneous vs. Exact (w/ I.F.)

    in Analysis and Calculus

    Posted

    Hello!

     

    My D.E. exam is tomorrow, and I was wondering something (but don't have the time to try it myself).

     

    Say you have a first order diff. eq.:

     

    e.g.

    M(x,y)dx + N(x,y)dy = 0

     

    Now, say that one method to solve it in y is to use the homogenous method, then seperating (i.e. y = v(x)*x, dy/dx = ...)

     

    Could an integrating factor solve this equation too (in general)?

     

    More specifically, an integrating factor w/rt to only one variable, either some u(x) or u(y) [such that Mu dx + Nu dy = 0 is an exact D.E.].

     

    Thanks!

    0

    Radian

    in Mathematics

    Posted

    I think the idea of radians is useful, because it relates the arc length, radius, and the angle subtended. In addition (like Matt said), it's useful in Calculus because degrees don't work there.

     

    In addition, steradians use the same idea as radians, whereas relating steradians to degrees would be different.

    0

    Radian

    in Mathematics

    Posted

    I think the idea of radians is useful, because it relates the arc length, radius, and the angle subtended. In addition (like Matt said), it's useful in Calculus because degrees don't work there.

     

    In addition, steradians use the same idea as radians, whereas relating steradians to degrees would be different.

    0

    Firefox vs Internet Explorer

    in Computer Science

    Posted

    i dont like the way there is a massive Go button after the address bar. i mean noone uses it anyway. why keep it there? is there a way to get rid of the text "Go" or the button altogether?

     

    lol

     

    right click on the toolbar with File, Edit, ..., then click on customize

     

    Then click & drag the GO button off.

     

    btw: has anyone d/l the new update?

    0

    Firefox vs Internet Explorer

    in Computer Science

    Posted

    i dont like the way there is a massive Go button after the address bar. i mean noone uses it anyway. why keep it there? is there a way to get rid of the text "Go" or the button altogether?

     

    lol

     

    right click on the toolbar with File, Edit, ..., then click on customize

     

    Then click & drag the GO button off.

     

    btw: has anyone d/l the new update?

    0

    Spare Computer

    in Computer Science

    Posted

    hm ... I will try to get my hdd working first before i try that wacky stuff.

     

    My cd drive used to use the primary slave, but I changed it to be the secondary slave because the new 2 GB hdd uses the primary slave now.

     

    My win98 still uses the primary master, but the comp does not read the new hdd or the cd.

     

    Any suggestions?

    0

    Spare Computer

    in Computer Science

    Posted

    yeah' date=' just buy an IDE cable, theyre well cheap and then plug it into your motherboard (assuming you have a spare IDE slot!) and then partition the drive and format it and that its all go.

    NB: IDE cable normally have 3 ports on, one to motherbaord, one to primary HDD and the 3rd for an extra HDD, so you may be able to use that!

     

    why would one use partition magic? windows has its own built in program which does it for you... unless you were using linux etc.[/quote']

     

    hm...I thought the IDE cable only goes from the motherboard to the device?

     

    Anyways, the HDD is already formatted & my friend is giving me an old 40pin IDE cable on Monday. I hope all goes well. :D

    0

    Essential Firefox Extension.

    in The Lounge

    Posted

    Sorry to dig up an old thread, but I was wondering if there is any way to change Firefox's bookmark logos?

     

    Some sites (e.g. the vB ones) have a default icon that appears to the left of the url, and it the icon is defaulted onto the bookmark one, though most are blank with the default page icon.

    0

    Spare Computer

    in Computer Science

    Posted

    Just fork out £30 or so and buy a small hdd to shove linux (or win98) on. Makes life a lot simpler.

     

    haha

     

    I have a spare 2GB hdd that my uncle gave me, but the problem is that I don't have any extra IDE cables (or whatever it is that I plug into the hdd) emanating from my board, or wherever it comes from.

     

    Can I purchase a IDE cable and add it on myself?

     

    In addition, I was worried about Linux's safety.

    i.e. http://www.linuxgazette.com/issue34/vertes.html

     

    I'm under the impression that Linux is strong in that malware cannot execute because it is a non-windows environment. However, I'm worried about instrusion attempts against Linux from outside the web.

     

    For example, Windows has a variety of safety features bunched with it's OSs (e.g. alg.exe, lsass.exe) (whether they are effective or not is not the point atm :P). Do certain linux 'distros' have better security features than other, if any?

     

    Thanks!

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