# Search results

1. ### Finite Fourier Transform on a 3d wave

Finite Fourier Transform on a 2d wave How does the finite fourier transform work exactly? The transform of f(x) is \widetilde{f}(\lambda_{n}) =\int^{L}_{0} f(x) X_{n} dx If I had a 3d wave equation pde and I applied Finite fourier transform on the pde for z(x,y,t)=X(x)Y(y)T(t)...
2. ### Proof using f(x1,y1)-f(x0,y0)=fx(x*,y*)(x1-x0)+fy(x*,y*)(y1-y0)

1. Homework Statement [/prove f(x1,y1)-f(x0,y0)=fx(x*,y*)(x1-x0)+fy(x*,y*)(y1-y0) prove there exists a point (x*,y*) if fx and fy are all continuous on a circular region and contain A(x0,y0) and B(x1,y1) 2. Homework Equations [b]3. The Attempt at a Solution I'm thinking mean value...
3. ### How do you tell what a vector space will look like from it's spanning set.

I know that, and it's not really my question unless I misunderstand the applications of what you just said. My question pertains to the visible nature of it.
4. ### How do you tell what a vector space will look like from it's spanning set.

I'm having a hard time visualising them. How do you plot vector fields How do you plot spanning sets? How do you tell if something spans a plane, 3d, a line or more dimensions.
5. ### Basic basic javascript form validation. literally need an help

Javascript is in an external file liked by this: <script type="text/javascript" src="myscript.js"></script> in the head tag i have <form name="myform" action="" method="POST" onSumbit="return validateForms()"> and some form stuff and then: <input type="submit" value="Submit"...
6. ### What does 2nd ord pde tell you? like fxx(x,y)

is there a graphical representation of what it looks like?
7. ### Implicit partial differential for unknown function F(x,y,z)=0

1. Homework Statement F(x,y,z)=0 x=a(y,z) y=b(x,z) z=c(x,y) what does \frac{\partial c}{\partial x} \frac{\partial b}{\partial z} \frac{\partial a}{\partial y} equal. 2. Homework Equations maybe you could tell me? 3. The Attempt at a Solution i've spent hours and hours...
8. ### What does 2nd ord pde tell you? like fxx(x,y)

pure and mixed, what do they tell you about a function?
9. ### Wht does this sign mean?

(\frac{\partial z}{\partial x})y the small y, what does it mean. the context this is used in is F(x,y,z) where each variable is a function of the other 2 variables.
10. ### Volume under curve z=1-x^2-2y^2

1. Homework Statement z=1-x^2-2y^2 find volume under curve bounded by the xy plane. is the answer sheet wrong? (see below) why am i struggling so much with this??!?!?! how do i do it? 2. Homework Equations according to other answer sheet, it is pi/sqrt 2 3. The Attempt at a...
11. ### Vector space prove 0u=0

1. Homework Statement prove 0u=0 where u is in the vector space. 2. Homework Equations the 10 various axioms for addition and scalar multiplication. 3. The Attempt at a Solution pretty much just (u+-u)u=0 or (1-1)u=0 1u+-1u=0 and then i get stuck. i can prove that...
12. ### Show its not a group for # where a#b=a+b-ab in the set of all real numbers

*facepalm* thanks!
13. ### Show its not a group for # where a#b=a+b-ab in the set of all real numbers

1. Homework Statement In set theory, i have a two part question, the first is showing that the system S={set of all real numbers( \Re )}, #} where a#b=a+b-ab we have to show that it's not a group. and then find what c is so that the system = { \Re \cap\overline{c}, # } is a group. 2. Homework...
14. ### Why do some people think women suck at science and math?

Re: Why do some people think women "suck" at science and math? i'm a female who studies BA of maths, ive always been good at maths and i actually think im rather good looking. tall, blonde, blue eyes, slender, etc i have guys falling for me quite a fair bit too. But i think theres this...
15. ### 3-10 points why you believe in the theory of evolution and big bang

Can you give me 3-10 points why you believe in the theory of evolution and/or the big bang? this is independant of any other theories. I'd like it numbered. and just brief points, like a topic and brief explanation of why this makes you believe evolution and/or the big bang to be true. I'll...
16. ### What is 3 digit arithmetic?

the context was talking about floating point numbers and catastrophic cancellation in the quadratic equation. it said using 3 digit arithmetic: *subs in some numbers, 0.2, 100.9 etc into the quad equation and at the end rounds the entire number to 3 digits* am i right in assuming that...
17. ### What is 3 digit arithmetic?

what is 3(or i, where i=1,2,3,4......∞) digit arithmetic? is it just working with 3 decimals or 3 significant figures? or is it base 3 arithmetic?
18. ### RFID attendance marking, what infrastructure?

RFID attendance marking, what infrastructure?? im trying to plan for an RFID system. 1)what resources and material and general infrastructure do i need? 2) i think i want it to connect it up to my Uni's intranet maybe wireless, so i'd only need to wire the power source? this good? 3)...
19. ### Is it wrong to have a back-up arranged before a breakup?

You should already have dumped the poor girl before you decided to look elsewhere. as a girl id find that extremely unattractive. Id also refuse to date you because if I did, then youd be likely to look elsewhere while youre dating me.
20. ### Conditional Probability

i just did P(R∧Mon | W) + P(R∧Mon| Wˉ) = 0.2+0.05=0.25 so, this isnt right???
21. ### MATLAB Basic matlab q on writing error messages

How do you write error messages for when a function has been given an input that is illogical for what the function does. in matlab function b = bla(a) for example if a < 0 i want it to display a message
22. ### Conditional Probability

1. Homework Statement romeo proposed to juliet. now hes waiting for her response. R = 'event that she replies' W='event that she wants to get married' Mon = 'event on monday' Tue = 'event on Tuesday' P(R\wedgeMon | W) = 0.2 P(R\wedgeTue | W) = 0.25 P(R\wedgeMon| \bar{W}) = 0.05...
23. ### MATLAB Matlab and floating point, function for min n max?

so i found this program matlab on the computers at uni. ive been messing around with it. right now im learning a bit about floating point systems and stuff and i thought it would be cool to write up a function that finds the smallest and largest numbers but turns out its harder than i first...
24. ### Questions and answers for a test covering a variety of things?

im trying to study but i have um misplaced my textbook. (it ran away from me, after i neglected it whilst doing other assesments) so i would greatly appreciate just a couple questions with answers, (feel free to give me more though ;) ) on any of these things (in order of priority) -...
25. ### When integrating by trig substitution why do you use what you use?

Re: when integrating by trig substitution why do you use what you use?? thanks guys!
26. ### Check my working for finding if vectors are parallel ?

thanks tiny-tim hehe sorry, im pretty bad at that HallsofIvy. and ummm no?? i dont think so... :S does that in itself tell us that it is not parallel? so... it is correct the way i did it? even if it perhaps wasn't the simplest?
27. ### When integrating by trig substitution why do you use what you use?

Re: when integrating by trig substitution why do you use what you use?? sorry, how did you sub u into sinh(2u) isnt that just sinh(2sinh^-1(x)? how did you simplify?
28. ### Check my working for finding if vectors are parallel ?

hmm. well, we're supposed to use the stuff we are learning about right now. i was told by my teacher that i could use either dot or cross on the lines. he did an example for an equation for a line with two variabkes (s and t) and found the normals (another equation with i,j and k in it...
29. ### Check my working for finding if vectors are parallel ?

the question asks for the equation of the lines. so i did that. i posted to see if i made any errors are my answers correct or are they not?
30. ### Check my working for finding if vectors are parallel ?

1. Homework Statement there is a line through A : (1;-2; 1) and B : (0; 2; 3) and the line through C : (4; 1;-2) and D : (2; 2; 2) are they parallel? 3. The Attempt at a Solution i said no they weren't. i had the lines as being: (-t+1)i+(4t+2)j+(2t+1)k and (-2t+4)i+(t+1)j+(4t-2)k...