# Search results

1. ### D'Alembert's principle

Hey guys, I'm stuck on this problem! I have no idea how to even go about solving it. I tried searching the net for D'Alembert's principle but nothing was helpful. Any suggestions on how to go about solving it will be much appreciated! Homework Statement Find with the aid of D’Alembert’s...
2. ### D’Alembert’s reduction principle

this is an ODE. FS stands for fundamental system.
3. ### D’Alembert’s reduction principle

Hey guys, I'm stuck on this problem! I have no idea how to even go about solving it. I tried searching the net for D'Alembert's principle but nothing was helpful. Any suggestions on how to go about solving it will be much appreciated! Find with the aid of D’Alembert’s reduction principle the...
4. ### C program display time

Yes, that's correct. So if I do the following seconds=ticks*2 minutes=seconds/60 hours=minutes/60 how do I then use those values to display the correct hours, minutes? for example I have 3602 seconds, that will be 60.0333333 minutes, and 1.00055556 hours
5. ### C program display time

Ok, I have to write a program that displays an arbitary time. I'm given 2 ticks every 1 second. So I'm suppose to use that to display the Hour, minute and seconds...im not sure where to start on how to create this. I know to find seconds I just do ticks/2, but for minutes and hours I'm confused...
6. ### Simple inverse fourier transforms

Can someone please tell my what the inverse Fourier transform of t*u(t) is?? I've been looking at tables but there isn't anything for just t...
7. ### Please, ive been stuck on this inverse laplace for awhile

See, I haven't learned the method of residues...This problem is for my signals and systems class and I'm only allowed to use inverse laplace methods.
8. ### Please, ive been stuck on this inverse laplace for awhile

Actually I just realized my Y(s)=s^2 / [(s^2+4)^2*(s^2+2)^2] so s=2i, s=-2i, s=sqrt(2)i, s=-sqrt(2)i Thus, resulting in no repeating roots. But I still have problems coming up with the coefficients. I think you setup the partial fraction like this: As+2B/(s^2+4)^2 +...
9. ### Please, ive been stuck on this inverse laplace for awhile

I have to find the laplace inverse of a function y(s) which has repeated complex roots. Y(s)=s^2 / (s^2+4)^2 so s=2i, s=2i, s=-2i, s=-2i. My partial fraction is as follows: A/(s-2i) + B/(s-2i)^2 + C/(s+2j) + D/(s+2j)^2 I use the standard method for finding regular repeated roots but...
10. ### Electrical engineering jobs?

I'm currently majoring in Electrical engineering as I stated above...
11. ### Electrical engineering jobs?

I'm currently in my third year of college majoring in electrical engineering. I'm just now starting to worry about the different kind of jobs that are available out there. I was hoping some electrical engineers can describe their typical days at work. I just have no clue to what exactly a...
12. ### Understand Laplace alot better now

So for the problem: g(t)=t^2 * sin(3t) * x(t) How would you go about transforming that? This is my first encounter of 3 terms...
13. ### Understand Laplace alot better now

Ok, I'm starting to understand Laplace a lot better now. But I have, hopefully, my last question. If you have a function like g(t)=t^2 * sin(3t) * x(t) where x(t) has an already defined laplace transform. do you actually include x(t) in your laplace transformation? Because when I see...
14. ### Laplace transforms

What happens to u(2t-5) though? Do you actually take the Laplace transform of that?
15. ### Laplace transforms

Ok, this is the question: Assume that the Laplace transform of x(t) is given as X(s)=s / (2s^(2) + 1). Determine the Laplace transform of the following function. g(t)=x(2t-5)u(2t-5) How do I use the transform they have given me to solve this...I guess my major problem lies using time...
16. ### Response of System

Ok, so X(s) is the Laplace transform of the function x(t) and S(s) is the Laplace transform of s(t)=t*e^(-2t) u(t)? So is H(s) the response of the input? I don't see when you would do inverse Laplace... Sorry, but this stuff is 100% new to me, we definitely didn't talk about this yet. But it...
17. ### Converting to unit impulse function

So would it be ramp(t)+ramp(-t-1) If that's the case, then how would you find the Laplace of that when it replaces tri(t-1)?
18. ### Converting to unit impulse function

I was wondering how do you go about converting something like tri(t-1) to the unit impulse function. How do you convert any function to a unit impulse function? More specifically I'm trying to find the Laplace transform of x(t)=[tri(t-1)]e^(-3t) And I was told you have to convert the...
19. ### Response of System

Is there another way to do this problem? I don't think we've done transfer functions yet. All we've done so far is basic signals stuff like graphing impulses, find signal energy and power, proving linearity, time-invariance, etc and convolution and basic laplace.
20. ### Response of System

The question is as follows: The step response of a linear time-invariant system is given as s(t)=t*e^(-2t) u(t) Determine the response of the system to the following inputs: a. x(t)=sin(3t) u(t) b. x(t)=tri(t-1) As of now I see this problem and I have no idea what it means...I tried...
21. ### Signals and Systems questions

I have a question about finding the signal energy of a signal? What exactly are you suppose to do when you are given a certain function like x(t)=rect(t) sin(2*pi*t)?
22. ### Solving op amp circuits.

Yes, it's an ideal op-amp.
23. ### Solving op amp circuits.

I have to solve an op amp circuit for a lab I'm doing but the circuit they have given me looks confusing (it's on page 46, http://filebox.vt.edu/users/oshekari/Manual_Student.pdf). Why does the 4.7k ohm resistor have an arrow pointing to the middle of the 100 ohm resistor? I know the 100ohm is a...
24. ### GCD proof

I'm having trouble with gcd proofs in general, but here is a specific problem. Let a and b be integers, not both zero, and let d be a positive integer that divides both a and b. Then there exists a1 and b1 such that a=a1*d and b=b1*d. Prove that d=gcd(a,b) if and only if 1=gcd(a1,b1) What...
25. ### Using inductors to reduce electric bill?

Using inductors to reduce electric bill?? My professor today mentioned that if you place an inductor in one of the power outlets in your house will allow actually produce no power and will cause your electric bill to reduce since that specific outlet is causing the power meter to reverse its...
26. ### Proof by induction

But where did you come up with the base cases needing to be n=1 and n=2. My teacher tried to explain a mathematical way of figuring out the base cases to use but I couldn't follow it.
27. ### Proof by induction

But my teacher has told us that in this specific problem there are more than one base case needed.
28. ### Proof by induction

The following question has been giving me problems because I'm stuck trying to find what the base cases would be. Let m be a given positive integer with m>=2(So m remains constant throughout the problem) Let fn be the sequence of fibonacci numbers. Prove that for every integer n>=1, fm+n=(fm...
29. ### Global extrema question

That's the thing, when I look for the points where the partials are 0, I get (x=pi/2), (x=3*pi/2) and (y=pi), (y=2*pi). And when I evaluate the function at the corners which are (x=0), (x=2*pi), (y=0), (y=2*pi), I get x=0, x=0, y=1, y=1. So I don't see how I can get -2,2 even though I know I...
30. ### Global extrema question

Ok, I'm starting to understand this a little better now. Now my new question is when you have the domain be something like 0<=x<=2*pi, 0<=y<=2*pi, do you have to actually go through each value and see which combination gives you a maximum? Because in the case of f(x,y)=sin(x)+cos(y), the...
31. ### Global extrema question

How do I do this using calculus though, so I know what to do for other problems that arise. I know I must find the partial derviative for f(x,y) and find the critical values of each of those, which I believe are (pi/2, pi), (3*pi/2, 2*pi). Then I'm suppose to do something with the rectangle but...
32. ### Global extrema question

I'm supposed to find the absolute max and min for f(x,y)=sin(x) +cos(y) on the rectangle defined by 0<=x<=2*pi 0<=y<=2*pi. Can someone point me in the right direction. I got the critical points but i don't know what to do after that.
33. ### Relations between sets proofs

I'm trying to prove the following by contradiction: [(A^B)-(B^C)]-(A^C)'=0. A, B, C are sets. All I know is in order to prove by contradiction you simply set the above not equal to zero. But I don't know where to go from there. "^" means the intersection symbol.
34. ### Vector geometry help

So, how would you go about finding a line that is perpendicular?
35. ### Vector geometry help

Wouldn't (3,1,-2)+t(1,1,1) be correct for the line perpendicular to x=-1+t, y=-2+t, z=-1+t since the vector <1,1,1> is coming from that?
36. ### Vector geometry help

I have a question about solving the following problem "Find the line through (3,1,-2) that intersects and is perpendicular to the line x=-1+t, y=-2+t, z=-1+t." My question is regarding the intersection part, I know how to find the equation of the line that is perpendicular to another line...
37. ### Architecture Help

I need some help with the PIC (PIC16F84) architecture. I am suppose to write timing diagram, including values of the PC (program counter), for the following instruction sequence when (a) the BTFSC (bit test register f, skip if set) instruction results in a skip and (b) when it does not...
38. ### Several optics questions, need of desperate help.

Any help at all will be great.
39. ### Several optics questions, need of desperate help.

Several optics questions, need desperate help. I have some questions about optics. I've been working on these problems unfortunately over thanksgiving break and without a book (I forgot it to bring it) So any help you guys can give me will be awesome. 1. A concave mirror has a radius of...
40. ### Solving a hard equation

I have the given equation: (6^x+6^-x)/6 = 2. How do you solve this?
41. ### Assembly language programming?

Yeah, that would be fine. I'm interested in seeing how different it is.
42. ### Assembly language programming?

I'm using assembly language to program a PIC...PIC16F84 to be specific. I don't know, I guess it can differ?
43. ### Assembly language programming?

Does anyone have any suggestions?
44. ### Assembly language programming?

Ok, I'm understanding this a little better now, my other code was totally wrong. I'm suppose to perform the operation according to the opcode. If its 0x00 I increment, 0x01-decrement, 0x02-complement, 0x03-clear. My only question now is how do I look at the bits and see if it's a 0, 1, 2, or 3...
45. ### Assembly language programming?

This is my code as of now. I'm pretty sure it's totally wrong, but logically it seems right to me, increment 0x21, decrement 0x21, complement 0x21, and then clear it? I think it's just the memory stuff that's giving me a hardtime(i hope). list P=16F84 include P16F84.INC ; Define...
46. ### Assembly language programming?

I'm working on a project that I believe should be pretty simple to do if I actually knew assembly language. For my program I'm suppose to start at data memory location 0x30 and perform the increment, decrement, complement, and clear operations. The operations are all performed on location...
47. ### Write the system in equation form?

Hi, I'm given a matrix and I need to write it in equation form so that I will have three equations, using x(t), y(t), and z(t) The matrix is a 3x3 [3 -2 0] x'= [-1 3 -2] *x [0 -1 3] I know how to rewrite it using only x(t) but I'm not sure how to do...
48. ### Repeated eigenvalues?

I'm trying to find the basis for a particular matrix and I get a 3 eigenvalues with two of them being identical to each other. What do I do to find the basis for the repeated eigenvalue? Will it have the same basis as the original number? Thanks!
49. ### 2-1 multiplexer using only nands and nots

I need to make a 2-1 mux using only NANDS and inverters. I thought it would look like a simple nand gate with another inverter attached at the end (basically a AND gate). However, that didnt work. I need it so when the selection input is a zero it selects whatever X0 is and when the selection...
50. ### RTL circuit design, need some help, please!

I have to design a circuit that does the following operations: Add L to w w<--w+L Increment w w<--w+1 arithimetic left shift w w<--arithemetic left shift of w 2's complement of w w<--w'+1 Bit-wise complement of w w<--w' load L...