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do you think we will know?

I don't know much about physics, but I was wondering the other day whether what I was thinking was a popular theory. If time is like a one dimensional line and it starts at the orgin and it grows like a vector along the line as time progresses, then wouldn't it only be possible to travel back...

What is wrong someone getting interested in science after reading a book?

I have never heard of anyone ever switching from EET to EE as and undergraduate. Is your EET program a BS degree? I was an EE major up till last semester then I switched to EET because I simply couldn't handle the EE program.

Go to your financial aid department. I get plenty of grants, and I am a "B student". All I had to do was file for financial aid.

I am an EE/CpE major. I am entering my "Junior Year" (I am really a second year junior because I played around too much the last couple of semesters. I did not pursue an internship over the summer, but still wanted to work. So I worked at Radio Shack all summer. I think that it is...

I definitely agree with you guys. But I find it very difficult to study for a class when I am not "forced to". I know I am never actually forced to, but I think you know what I mean. I call this the "force factor"! I have tried many times to teach myself a subject or topic, but I really don't...

At Radio Shack they sell a micro-controller kit that is pretty neat. As for reading material, I hear that Bebop the Boolean Boogie is a good book.

I recently acquired a Texronix 454 and would now like to purchase a function generator. What would be a good cheap f.g. to accompany the 454.

OK. So I found the toolbox I need. It is called the control system toolbox. PLEASE help me figure out how to get it!

Still can't figure out how to get the new toolboxes. Could someone please help?

Cool. Thanks.

I have tried. How about you tell me if you know?

I found it on the mathworks website, but you have to buy it. Do you know where I can find this toolbox for free?

when i type help tf it says: tf.m not found. How do I get it?

I am trying to find the transfer function for a simple RL circuit. At my school they don't use version 7, and I was able to find it with this code: NUM = 20e3; DEN = [1 20e3]; sys = tf(NUM, DEN) That found the transfer function for the RL series circuit with a 20K resistor and a Inductor with...

Anyone?

I want to graph the equation z = x^{2} + (xy) in matlab, but I can't figure out how to do it. Here is the code I am trying: EDU>> [X,Y] = meshgrid(-10:.5:10); EDU>> Z = X.^2 + X. * Y.; EDU>> mesh(X,Y,Z, 'EdgeColor', 'black') What am I doing wrong?

Awesome! Thanks!

I have tried that, but I still don't understand how to do it. If someone could write the code to do what I am trying to do for those two equations I gave, then I would be EXTREMELY grateful.

So do I take the cross product of (8,-1,3) and (3,-1,1) to find the normal vector?

I don't see what I have written that is wrong.

Alright, the I am finished with the corrections.

The correct answer is 5x +2z = 25 What am I doing wrong?

Homework Statement Find a plane that is perpendicular to the line \vec{L}(t) = (5,0,2)t + (3,-1,1) and passes through the point (5,-5,0) Homework Equations The equation of the plane that P through (x_{0},y_{0},z_{0}) that has a normal vector \vec{n} = A \vec{i} + B \vec{j} + C\vec{k}...

Anyone?

I am taking a vector calculus course and am having trouble figuring out how to graph things in Matlab to verify my answers. Here is exactly what I want to do: I want to graph side by side two different graphs simultaneously, so I can compare them. I will give you the equations of the two...

I am trying to make a circuit that works basically just like a traffic light. I want to use LED's and a 555 timer. So I want the first LED to be lit upon applying a voltage, then I will use some type of switch that activates the next LED to light up and stay lit for a specific amount of time...

Disregard this post. Sorry.

Homework Statement The donor state for tellurium (Te) in GaAs is 5.9 meV below the conduction band (E=E_{c}). At room temperature, what fraction of the states are empty if the Fermi energy lies 0.1 eV below E_{c} Homework Equations E_{c}|_{GaAs}= 1.42eV E_{d}= E_{F}=...

Yeah gokul, that is exactly what I am talking about.

Yeah, I am looking for the second closest distance, sorry.

Ya, you are right. Huh... I found that definition on the internet, so that is not the definition my book uses. In fact the lattice constant is not even defined in my book! (It is Neaman's Semiconductor device physics). But I am trying to figure out the distance between the two closest...

a is not the distance of the two closest atoms.

Yeah, I want to calculate it theoretically. OK, here is an example: Given: The dimensions of a diamond structure unit cell are (length, width, height) = (a,a,a). Find: The lattice constant for the diamond structure.

So how would I find the lattice constant of Si (of course in the diamond structure). It seems to me that you would need to know the radius of the atom to find the lattice constant.

Okay, here is the definition of the lattice constant I am referring to: The lattice constant refers to the constant distance between unit cells in a crystal lattice. Lattices in three dimensions generally have three lattice constants, referred to as a, b, and c. However, in the special case of...

I'll post an example of what I am talking about tommorow.

Yep. It is semiconductor physics.

Will someone please give me a link that explains how to find the "lattice constant" of certain atoms. Or could someone please walk me through the process of how you find the lattice constants. Thanks in advance:smile:

If I were you I would double major. Math is fun, and if you like it that is great. But if you are also worried about having a good job in the future, then I would say don't drop the CS major. But if you like math, then deffinetely go for both. As long as you or your family can afford the...

I'm not sure, but I have a feeling that everyone in here is going to say that your GPA is more important. Just curious, what are the math courses?

So berkeman, could I build this thing and put a speaker on it to transmit the sound frequency at 24kHz? http://www.goldmine-elec-products.com/prodinfo.asp?number=C6816

Ya, but how fun is that? I really just want to build it.

To shut a neighbors dog up! Essentially I want to build an electronic dog whistle.

I guess what I really mean is an Ultrasound Pulse Generator.

Or does anyone know where I could find schematics of how to build something like that?

I want to build an electronic device that transmits ultrasounds (I guess that is in the LF frequency range [?]). Does anyone know where I can find a kit that creates ultrasounds?

Cool, cool. I think you have pointed me in the direction I needed. Thanks a lot buddy.

What do you mean? Aren't I supposed to find the values of x for which the solution is differentiable? Wouldn't that be all values of x except when x is zero (or when it is coterminal with zero)?